DEPARTMENT OF PHARMACEUTICS
AND PHARMACEUTICAL
TECHNOLOGY
FACULTY OF PHARMACY
UNIVERSITY OF BENIN
BENIN CITY
PRACTICAL MANUAL FOR
THE PHARM. D DEGREE
(Revised 2012/2013)
Revised & Edited By
Prof. R.S. Okor
Prof. M.A. Iwuagwu
Dr (Mrs) F.E. Eichie
Dr. M.I. Arhewoh
Pharm. J.E. Isessele
Dr. E.Q. Osazuwa
Prof. A.O. Okhamafe
Prof. A.O. Onyekweli
Dr. M.U. Uhumwangho
Pharm. S.O. Eraga
Pharm. J.O. Erebor
200 LEVEL
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LABORATORY RULES
1. Dressing:
A clean well ironed overall laboratory coat must be worn at all times
during the practical class. Male students should be dressed in shirt, tie
and leather shoes while females should be dressed in skirt, blouse and
low-heeled or flat sole cover shoes (No sandals, slip-on, or easy ware).
Wearing make-up, false eye lashes, jewelries and hair styles with loose
strands or locks of hair should be avoided.
2. Cleanliness:
Cleanliness is indispensable to good dispensing and every exercise
must receive the same meticulous care as if it were a doctor’s
prescription.
3. Accuracy:
Most errors in the compounding operation are the result of
carelessness or the use of improper equipment when translating one
system of weights and measures to another.
4. Replacing Stock Bottles:
Bottles of chemicals must be returned immediately after use and never
kept on the bench as the habit of accumulating bottles hinders smooth
working. Excess chemicals must never be returned to the stock
bottles.
5. Practical Notebook
A practical well-indexed thick back notebook is of great value in
revising and for future reference.
6. Equipment and Techniques used in Weighing:
Balances: It is the personal responsibility of each student to keep the
dispensing balance and weights scrupulously clean.
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WEIGHING TECHNIQUES
1. Place suitable weighing papers on each balance pan.
2. Release the pan arrest gently and make the necessary adjustment
using the leveling screws so that the pointer shows a rest point of zero
as indicated by equal swings to the right and left of the zero index
mark and then arrest the balance.
3. Place the appropriate weights on the left hand stainless steel pan.
4. Place the approximate weight of the material to be weighed on the
right hand watch glass and release the pan arrest gently to determine
whether too much or too little was added.
5. Remove or add the material using a spatula arresting the pan
mechanism after each transfer is made.
6. The weighing process is completed when a release of the pan arrest
shows a zero rest point.
SENSITIVITY OF BALANCE
Limits of error of about 5 per cent are allowed in most weighing and
measuring processes. The error inevitably results because the operator
cannot estimate the equilibrium point closer than about one index scale
division.
The pharmacist must ascertain the “sensitivity of the balance”. The
sensitivity of a prescription balance is defined as the weight usually
expressed in milligrams, required to produce a pointer deflection of one
scale division.
The minimum permissible weight is at least 20 times the sensitivity of
the balance to avoid error greater than 5 per cent.
EQUIPMENT AND TECHNIQUE USED IN MEASURING
1. Select the appropriate graduate i.e. with a capacity equal to or
exceeding the volume to be measured.
2. Hold the graduate by the base with your left hand. Elevate the
graduate so that the desired mark is at eye level. Then pour the liquid
decreasing the rate of flow as the surface of liquid approaches the
desired mark.
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GENERAL PROCEDURE FOR DISPENSING A
PREPARATION
1. Each student is expected to work on his/her own. If advice is needed,
it should be obtained only from the lecturer.
2. A glass cloth is for polishing containers; it will not be suitable for this
purpose if it used for wiping the bench – this is the function of a duster
(a small hand towel or cloth). Dispensable paper towels are provided
at the end of each bench for mopping up wet spillage. You will require
a pair of scissors, a pair of forceps, a black/blue and red pen (fine
point), a ruler and a calculator.
3. All work should be done in a clean and tidy manner. This minimizes
contamination of the products and is conducive to precision and
accuracy.
4. Read the prescription carefully and, if necessary, look up and copy out
the formula from the B.N.F. (British National Formulary), B.P.
(British Pharmacopoeia). Always use the most recent editions of these
books.
5. Check the doses of internal preparations (including suppositories and
enemas) and take into account the directions for use. Report any over
dosages to a member of staff.
6. If any ingredient is a poison (check this in the Poisons and T.S.A.
Guide) the weight or volume dispensed must be checked by a
registered pharmacist.
7. Use the B.P.C. Extra Pharmacopoeia or B.P. to confirm that there are
no pharmaceutical or pharmacological incompatibilities in the
preparation.
8. If you are unsure about the method of preparation to use, refer to
your previous dispensing schedules, which should be well indexed, or
to DISPENSING FOR PHARMAEUTICAL STUDENTS.
9. Look up the storage requirements for the preparation (if the formula is
in the B.N.C., B.P.C., or B.P) or the medicaments (if the preparation
is a special formulation not in one of these books). Protection from
light, storage in a cool place, etc. may also be necessary.
10. From the formula, work out the amounts to be used and write them in
ink, at the side of the prescribed amounts, to facilitate checking.
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11. Check your calculations in two ways if possible.
12. Collect the correct container.
13. If necessary, cut the label to fit the container but do not trim off the
name of the supplier (the faculty in this case). In general, just the
largest possible label should be used.
14. Write the main label and collect any special labels that are necessary.
Leave them in a conspicuous place.
15. Start making the preparation.
16. If for any reason a preparation is left unfinished, even for a few
minutes, a label must be attached giving details of the materials added.
The preparation must be protected from accidental contamination.
ADDITIONAL SAFETY PRECAUTIONS
1.
If a wrong figure or unit is written cross it out and write the correct
one above or at the side. Do not attempt to alter the wrong one.
2. Always protect the decimal point with a ‘0’ i.e. 0.1 not .1; since if
the decimal point is not written distinctly, there is a risk of giving a
times ten (×10) overdose.
3. Always write down details of every weighing and measurement.
4. Carefully check the labels of the stock bottles you use and watch
particularly for such words as:
(a) Compound; e.g. Compound Tragacanth Powder is different from
Tragacanth Powder.
(b) Concentration; e.g. Concentrated Compound Infusion of Gentian
is different from Compound Infusion of Gentian.
(c) Strong (Fort); e.g. Strong Coal Tar Solution is different from Coal
Tar Solution. Also, watch out for medicaments that have similar
names: e.g. Eucalyptol and Eucalyptus Oil. Terebone and
Turpentine Oil (Oil Terebinth).
APPROXIMATIONS
1. In general, approximations should not be made and, certainly, never
when the amount can be weighed or measured with the weights.
When they are unavoidable, approximations should be minimal and in
no circumstances greater than 5 per cent.
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2. Always write the correct amount first and show the approximation in
brackets at the side – e.g. 18.478g (18.48g).
USE OF STOCK BOTTLES
1. Check the label against the prescription before and after using the
bottle.
2. Hold the bottle with the label uppermost so that it can be seen during
use. As a result, an error may be detected. Also, liquid from the rim
will not run down the label.
3. Always use a spatula for weighing solids. This avoids fouling the neck
of the bottle. To keep out dust, hold the bottle as near to horizontal
as possible with one hand and remove the stopper with the little
finger and palm of the other. Unless the stopper is too large, keep it
in the hand; you will find that you can easily use the spatula with the
same hand. If it is essential to put the stopper down, place it the right
way up on a clean sheet of white paper.
PRESENTATION
1. Glass and plastic containers must be polished before issue. Polishing
should be done after, as well as before labeling, to remove gum and
finger- marks.
2. Acacia-gum labels will not adhere to plastics or metal containers; selfadhesive labels must be used.
NOTES ON WRITING-UP DISPENSING SHEETS
1. Prescription: Make an exact copy of the prescription as written.
Record the date.
2. Formula and Calculation of Doses:
(a) Where the prescription consists of a formula showing all the
ingredients to be used, record the quantity of each substance used
opposite the name of the drug to which it refers.
(b) Where the prescription refers to a B.P., B.P.C., or B.N.F.
preparation, record the official formula together with the official
quantities, and record as in the quantities used.
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(c) Record details of all calculations and formula used including those
for dilutions and trituration. For all oral and injectable
preparations, record the maximum B.P. or B.P.C. dose of each
active ingredient.
3. Specimen Label: Affix a duplicate of the label applied to the
product. Include also any auxiliary labels used; e.g. shake the bottle.
4. Container: Record details of the size and type of container used
together with any special container specification for the product. E.g.
test for t he limit of alkalinity of glass (L.A.G.).
5. Storage Requirements: Record the shelf life of the product and
details of any special requirements for storage, e.g. protect from
light.
6. Main Pharmaceutical Actions of the Active Drug(s): Make
brief notes on the main pharmaceutical actions of the active
ingredients in the preparation, in the context of the dosage form
supplied.
7. Clinical Conditions and Dose Regimen of Product: Note that
this action refers to the final dispensed product only, and not to other
dosage forms of the same drugs.
8. Methods of Preparation: Describe in note form, but in detail the
methods used.
9. Clarification: Where applicable, specify medium used.
10. Sterilization: Where applicable, record methods, time and
temperature.
11. Formulation Notes: Record details of additives, excipients,
colouring, and aids to formulation. Mention also any incompatibilities
encountered. If you have formulated the product, give the reasons for
your choice of formulation.
PACKAGING AND LABELLING OF DISPENSED
MEDICINES
See Cooper and Gunns’ Dispensing for Pharmaceutical Students (12th
Edn. Pp.13 – 30).
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A. Packaging:
The type of container used for dispensed medicines are only general
suggestions and the choice of packaging for individual preparations is made
solely on technical grounds.
Official recommendations on colours and changes of container for each
type of medication should be adhered to so as to help reduce the accidental
misuse of medicines.
The following points are to be noted in the packaging of dispensed
products.
1. All mixtures intended for oral use must be packed in plain bottles and
covered with plastic screw-caps.
2. All preparations intended for external use only (e.g. applications,
gargles, lotions, etc.) must be packed in fluted or ribbed glass bottles.
3. All preparations containing photo-labile (i.e. light sensitive)
ingredients are packed in amber coloured bottles.
4. Any thick liquid preparations such as emulsion, liniments etc are
packed in wide-mouthed bottles to allow for easy pouring out of
contents from the bottle.
B. Labeling:
The primary function of a label is that of accurately directing the patient
how and when the medicine should be taken or used. The label is an
important factor in the appearance of the final medicine and a high
standard in label presentation will do much to maintain confidence of the
patient. Therefore, every effort should be made to be competent on this
point.
A number of important requirements are listed below:
1. Label instructions should be LEGIBLE, NEAT AND WELL
BALANCED.
2. Choose the correct size of container for the product and match the
label size to the container.
3. Polish bottles before labeling.
4. Affix labels symmetrically on the container.
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5. Never have more than one unlabelled product on the bench at the
same time. Never place a fresh label over an old label. This is
seriously and potentially dangerous.
In general, labels for “Internal Medicines” adopt Black Prints and
those for “External Medicines” adopt Red Prints.
The main label should clearly state:
1. The quantity of the product.
2. The type of preparation e.g. “The Mixture” The Tablets”, etc. or
where so directed the actual name of the preparation. For example, if
any official (B.P.C., B.N.F. or B.P.) product is dispensed, it is not
necessary to declare on the label, the concentration of the active
ingredients. It is for instance sufficient to label the product as;
“AMMONIUM CHLORIDE AND MORPHINE MIXTURE BP 188.
Vol.I.”
3. Precise instructions for use by the patient.
4. The date of dispensing.
5. A reference number (if it is a private prescription)
6. The name of the patient.
7. The name and address of the pharmacy.
NOTE.
The word “POISON” should not appear on the label of a dispensed
medicine unless specifically requested.
C. Auxiliary Labels:
For some preparations, instructions which are specifically detailed on the
prescription must be given on the container. Such instructions serve to
amplify how the medicine is to be used or to guide the patient regarding
the best storage conditions. Auxiliary labels should be sensibly positioned
relative to the main label and should not be fixed on the main label. Here
are some examples of such auxiliary labels.
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AUXILIARY
LABEL
“SHAKE
THE BOTTLE”
“FOR
EXTERNAL
USE ONLY”
“NOT TO BE
TAKEN”
(A possible
Alternative
Label for these
products is)
“NOT TO BE
TAKEN
BY MOUTH”
CIRCUMSTANCES IN
WHICH LABEL
IS USED
(a) Liquid preparations which
are disperse systems.
(b) Liquid preparations where
precipitations or separation
is considered possible.
(a) All liquid preparations for
external application.
EXAMPLES OF
PREPARATIONS
FOR WHICH
THE LABEL IS
APPROPRIATE
Emulsions,
Suspensions
Applications, Lotions,
Liniments, Skin Paints.
(b) Solid
and
semi-solid
preparations for external
application.
Creams, Dusting
Powders, Ointments.
(a) Liquid preparation which are
not administered orally and
which are not applied to a
skin surface.
Ear Drops, Eye
Lotions, Eye Drops,
Inhalations, Nasal
Drops, Enemas.
(b) Solid dosage forms which
might inadvertently be
administered by oral route.
Inhalation, Pessaries,
Some Solutions,
Tablet, Suppositories.
D. Other Labeling Instructions.
A number of B.P. and B.N.F. recommendations form the basis of
additional labels.
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INSTRUCTIONS EXPLAINING USE AND
ADMINISTRATION
‘Immerse in water for a few seconds, place upon the tongue and swallow
with a draught of water’ – Cachets
‘To be added to hot, but not boiling water and the vapour inhaled for 5 to
10 minutes’ – Inhalations (unless otherwise directed).
‘Not to be swallowed in large volumes’ – Gargles (unless other-wise
directed).
‘Not to be applied to open wounds or to raw wounds’ – Dusting Powders
(surfaces of large area)
‘Warm to body temperature before use’ – Enema (large volumes)
‘Sip and swallow slowly without the addition of water’ – Linctuses.
INSTRUCTIONS EMPHASIZING CORRECT STORAGE
CONDITIONS
‘Store in a cool place’ - Capsules, creams, ointments, pessaries,
suppositories, and all liquid preparations.
For certain preparations such as diluted elixirs, diluted creams, eye drops,
eye lotions, eye ointments, and freshly prepared mixtures, specific periods
are indicated beyond which the preparations should not be used. In such
cases, an indication of the expiry date is more helpful than reference to a
period of time.
A general guide to the packaging and labeling of dispensed medicines
follows. Our own practice does not completely fit the official
recommendations. In particular, most of our bottles for liquid
preparations are quite few and obsolete and are all colourless. It is hoped
that more bottles and labels will be obtained in the near future to facilitate
correct dispensing practice.
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Applications: Coloured fluted glass bottles fitted with plastic screw-cape
with plastic or other impervious liners.
Labeling: “For External Use Only” in red.
Cachets: Airtight containers which give adequate physical protection.
Containers made of glass, rigid plastics, or extruded aluminum are
generally suitable. Use cardboard boxes, which are suitable for short
storage periods.
Labeling – See Section D above.
Capsules: Airtight containers which give adequate physical protection.
Containers made of glass rigid plastics, or extruded aluminum is generally
suitable. A suitable internal wadding may be required.
Labeling: Colour of label black.
Creams: Wide-mouthed, squat glass jars fitted with plastic screw caps and
suitable liners. Certain plastic containers may also be suitable, provided
they prevent evaporation of water vapour; plastic containers are unsuitable
for those preparations containing plasticizers such as methylsalicylate or
phthalate esters.
Labeling: “For External Use Only”.
Draughts: White glass bottles fitted with plastic screw caps with plastic
or other impervious liners. Such dose should be packed separately or the
exact dosage made plain on the label.
Dusting Powders: Cylindrical paperboard boxes or plain white glass jars
with sprinkler holes on the closure.
Labeling: “For External Use Only” Red or black label depending on the
nature of the product.
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Eardrops: Coloured fluted glass bottles fitted with suitable droppers.
Plastic dropper bottles are also suitable provided that the plastic is
compatible with the content.
Labeling: “For External Use Only” Red.
Elixirs: Plain white glass bottles fitted with plastic screw-caps with plastic
or other impervious liners.
Labeling: Black.
Enemas: Coloured fluted glass bottles with plastic screw-caps with plastic
or other impervious liners. Disposable flexible plastic containers are
suitable for some enemas provided that the plastic is compatible with the
content.
Labeling: See Sections C and D above. Red label.
Eye-Drops: Coloured, fluted glass dropper bottles which are capable of
being sterilized by autoclaving. Plastic containers are suitable for some
eye-drops provided that the plastic is compatible with the content.
Note: The glass must be neutral or soda treated screw-capped dropper
bottles and must comply with British Standard 1679; Part 5: 1965.
Labeling: “Not to be taken” Red label.
Eye Lotion: Coloured, fluted glass bottles fitted with plastic screw caps
with plastic or other impervious liners. Unprotected bulk closures should
not be used for eye lotions.
Labeling: “For External Use Only” Red label.
Eye Ointment: Sterile collapsible tubes.
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Gargles: White fluted glass bottles fitted with plastic screw-caps with
plastic or other impervious liners.
Labeling: “Not to be taken” Red. Directions for dilution may be
required. For those gargles directed to be swallowed after gargling plain
white bottles should be used.
Granules: Airtight containers which give adequate; physical protection
containers made of glass, rigid plastics, or extruded aluminum; are
generally suitable.
Labeling: Depends on the purpose for which the granules are to be used.
Inhalations: White fluted glass bottles fitted with plastic screw caps with
plastic or impervious liners.
Labeling: “Not to be taken”. “Warm to body temperature before use”.
Linctuses: Plain white glass bottles fitted with plastic screw caps with
plastic or other impervious liners.
Labeling: Black “To be sipped swallowed slowly”.
Liniments: Coloured fluted glass bottles fitted with plastic screw caps
with plastic or other impervious liners.
Lotions: Coloured fluted glass bottles fitted with plastic screw caps with
plastic or other impervious liners.
Labeling: Red. “For External Use Only”.
Lozenges: Airtight containers which give adequate physical protection.
Containers made of glass, rigid plastics, or extruded aluminum, are
generally suitable.
Labeling: Black.
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Mixtures: Plain white non-graduated glass bottles fitted with plastic or
other impervious liners.
Labeling: Black “Shake the bottle” for those mixtures containing insoluble
materials.
Mouthwashes: White fluted glass bottles fitted with plastic screw caps
with plastic or other impervious liners.
Labeling: Red. “Not to be taken”. Direction for dilution may be
required.
Nasal Drops: Coloured fluted glass bottles with a dropper. Plastic
dropper bottles are also suitable, provided that the plastic is compatible
with the content.
Labeling: Red and “For External Use Only”.
Ointments: Wide-mouthed, screw-capped, plain squat glass jars or
plastic jars metal or plastic flexible tubes with screw caps. Certain plastic
containers containing plasticizers such as methyl salicylate ester are not
suitable for some ointments.
Labeling: Red and “For External Use Only”.
Paints: Coloured fluted glass bottles fitted with plastic screw caps with
plastic or other impervious liners.
Labeling: “For External Use Only”. Red label for skin paints. Red label
“Not to be taken” for throat and gum paints.
Pastes: Wide-mouthed, screw-capped, plain squat glass or plastic jar
metal or; plastic flexible tubes with screw caps.
Labeling: Red and “For External Use Only”.
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Pastilles: Airtight containers, which give adequate physical protection,
containers made of glass, rigid plastics, or extruded aluminum, are
generally suitable.
Labeling: Black.
Pessaries: They should be wrapped individually in waxed paper, in metal
foil, or in some suitable form of strip packing. They should be dispensed in
partitioned boxes or in suitable plastics containers (for 4g pessaries use
120g ointment jars).
Labeling: Red. “Not to be taken”.
Powders: Bulk powders should be dispensed in airtight containers, which
give adequate physical protection. Containers made of glass, rigid plastics,
or extruded aluminum, are generally suitable. Individually wrapped
powders should be dispensed in stout paperboard boxes with bonded
plastic membrane plastic boxes with bonded plastic membrane, plastic
boxes or folding paperboard cartons, which give adequate physical
protection. Powders containing deliquescent or volatile materials should
be double wrapped in greaseproof paper.
Labeling: Black. Instructions for administration should be included.
Solution – Tablets: Airtight containers, which give adequate physical
protection. Containers made of glass, rigid plastics, or extruded
aluminum, are generally suitable.
Labeling: Red. “Not to be taken” for tablets used to prepare external
solutions.
Spray Solutions: White fluted glass bottles fitted with plastic screw-caps
with plastic or other impervious liners.
Labeling: Red. “Not to be taken”.
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Suppositories: As for pessaries.
Tablets: Airtight containers which give adequate physical protection.
Containers made of glass, rigid plastics, or extruded aluminum, are
generally suitable. Foil or strip packed tablets should be packed in suitable
paperboard boxes or folding paperboard cartons which give adequate
physical protection. Internal wadding may be necessary.
Labeling: Black.
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SCHEDULE 1
HOUSEHOLD MEASURES AND WEIGHING OF SMALL
AMOUNTS OF MATERIALS.
Although medicines are prepared in the pharmacy with professional
accuracy, they are administered in the home with available measures,
called the household measures. Studies have shown that these household
measures may vary in capacity.
(a) Measure the Capacities of the Following Household
Measures:
1 – Teaspoonful
5ml.
2 – Dessertspoonful
10ml.
3 – Tablespoonful
15ml.
(b) Measurement of Drop Volume.
Measure the volume of drops obtained from different liquids, e.g. water,
alcohol and glycerin, using various droppers. Comment on the result.
Equipment for Weighing:
Under the weighing and measures regulations (1963), weighing
instruments for certain retail transactions are graded, according to design,
construction, and performance, into two categories, viz:
Balances
Beam scales marked “Class B” and
Beam scales marked “Class C”.
For dispensing purposes, beam scales marked “class B” are generally used
and are the types we have in the laboratory. They satisfy the requirements
stipulated in the regulations for weighing instruments used for
transactions, by retail in drugs and other pharmaceutical products.
19
Class B dispensing balance has a capacity of 50g, a sensitivity of 20mg and a
maximum error of 20mg.
NB/Sensitivity – is the minimum weight to which the instrument
responds.
Error: is the possible inaccuracy at full load.
Minimum Weighable Quantity:
Since it is generally accepted that the error in the amount of any
ingredients in a dispensed preparation should not be more than 5%, the
minimum weighable amount is 100mg. Smaller amounts than 100mg (or
300mg for potent substances) should be weighed on a high quality
analytical balance or obtained by trituration.
(c) Weighing of Small Quantities of Powders by Trituration:
This is the method employed in pharmaceutical formulations, and a
trituration is a term applied to a mixture or dilution of a substance with an
inert one. Small quantities of finely powdered solids are mixed on a sheet
of white paper by means of a powder knife or spatula. The rule is to add a
little of the substance present in lesser amount (usually the more potent
substance), and mix intimately. The remainder of the substance present in
greater amount is then introduced into the mixture in very small quantities
at first but gradually increasing the quantities; until the whole substance is
used up (It is impossible to ensure intimate dispersion of one powder in
another by mixing the two substances all at once).
For powders weighing less than 100mg a trituration must be made using
lactose or other inert diluent and an aliquot portion is taken. The
trituration may be obtained by making all in 10 or 1 in 100 dilution.
PRACTICAL
Weigh 15mg of Atropine sulphate.
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SCHEDULE 2
AROMATIC WATERS
Synonym: Aromatic Water
These are aqueous solutions, usually saturated, of volatile oils or other
aromatic substances in water. Some of them have a mild therapeutic
action, but they are mainly used for their flavouring properties as vehicles
for the internal administration of medicaments.
Preparation of Aromatic Waters:
Aromatic waters are prepared by one of the following general methods:
1.
Dilution from concentrated waters. The concentrated water diluted
with 39 times its volume of water.
2.
Solution (There are two methods):
(a) The essential oil is shaken with 500 times its volume of water; the
shaking is done at intervals during about 15 minutes, and allowed
to stand for 12 hours and filtered.
(b) The volatile oil is triturated with a sufficient quantity of purified
talc or kieselguhr or pulped filter paper and 500 times its volume
of water is gradually added while stirring, and filtered.
3.
Distillation: The drug or essential oil is distilled with water until the
specific volume of distillate has been collected. The distillate is shaken
thoroughly, allowed to stand for not less than 12 hours and any excess
oil removed.
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PRACTICAL
1. Prepare 100ml of Chloroform Water BP (Double Strength)
Synonym: Chloroform Water.
Note: You will have to check the B.P. 1973 for the formula and prepare
100ml ONLY of the formula.
2. Prepare 100ml of Concentrated Peppermint Water BP
Synonym: Concentrated Peppermint Water.
Note: Check BP 1973 for the formula and prepare 100ml only of the
formula.
3. Prepare 100ml of Peppermint Water BP by diluting conc. Peppermint
Water BP you prepared in No. 2 above, with 39 times its volume of
water. Comment on your practical note books:
The storage conditions, action and uses of the preparations.
BP Preparation of Normal Saline:
Normal saline (0.9% w/v sodium chloride) is isotonic with blood serum,
lachrymal secretions (tears) and nasal secretions. It is therefore used as the
vehicle for preparations that require adjustment to iso-osmoticity such as
parenteral solutions, ophthalmic solutions and some nasal drops. (See
Dispensing for Pharm. Students – 324).
4. Prepare 0.9% w/v sodium chloride in purified water; Send 200ml.
22
SCHEDULE 3
SIMPLE MIXTURES CONTAINING READILY SOLUBLE
LIQUIDS
Synonyms. Mixtures, Oral Liquids, Oral Solutions.
Mixtures are liquid preparations intended for administration by mouth and
consist of one or more medicaments dissolved or suspended usually in an
aqueous vehicle but occasionally in a suitable non-aqueous vehicle. They
are normally dispensed in a container, which holds several doses.
Classification of Mixtures:
1. Simple mixtures containing soluble substance
2. Mixtures containing diffusible solids
3. Mixtures containing indiffusible solids
4. Mixtures containing precipitate – forming liquids
5. Mixtures containing slightly soluble liquids.
SIMPLE MIXTURE CONTAINING SOLUBLE
SUBSTANCES ONLY
General Method of Preparation:
These are prepared by dissolving the weighed solids to about three
quarters of t he vehicles, without previous powdering, in a suitable
container. The liquid ingredients are added and after measuring each of the
liquid, the vessel used is rinsed with a little of the vehicle and the contents
are added to the mixture. The mixture is transferred to the dispensing
bottle in which it is made up to volume with more of the vehicle and the
label is attached.
Containers for Mixtures:
Plain white glass should be used. The bottle should be fitted with a plastic
screw-cap with plastic or other impervious liners.
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PRACTICAL
Dispense the following:
1. Drugs Readily Soluble in the Vehicle
℞ Ammonium Chloride and Morphine Mixture BP 1988
Synonym: Ammonium Chloride and Morphine Mixtures
Ammonium Chloride
Ammonium Bicarbonate
Liquorice Liquid Extract
Chloroform and Morphine Tincture
Water to
Send 50ml
Let a mixture be made
Label: Three time daily.
30g
20g
50ml
30ml
1000ml
Follow the General Dispensing Procedure:
(a) Copy the prescription into the LHP of your practical book
(b) Check the principles underlying the product
(c) Calculate the quantities of materials required and enter these values
into the appropriate column of your practical book
(d) Write the method of preparation on the top of the LHP of the
practical book, and
(e) Dispense the prescription.
Method of Preparation:
(i) Weigh the ammonium salts and transfer to a beaker. Add some
vehicle and stir to dissolve the salts.
(ii) Measure the liquorices liquid extract in a pipette (check) and transfer
to the measure.
(iii) Measure the chloroform and morphine tincture, but shake it well first
because it separates on standing. Add more vehicle and transfer the
24
mixture into a dispensing bottle. Shake the bottle and make up to
volume.
(f) Label the product – check label, calculations and critically examine the
mixture for faults.
(g) Complete the practical book description of the preparation.
2. Solution of Drugs not Readily Soluble in the Vehicle.
These may often be more quickly prepared by grinding the solid in a glass
mortar before weighing and heating with water to a beaker. This does not
apply if the vehicle contains volatile ingredients.
℞ Paediatric Ferrous Sulphate Oral Solution BP 1988
Synonym: Paediatric Ferrous Sulphate Mixture.
Ferrous Sulphate
12g
Ascorbic Acid
2g
Orange Syrup
100ml.
Chloroform Water D/S
500ml.
Water to
1000ml.
Send 50ml.
Label – One desert spoonful to be taken after food daily. Cochleire
mediumegter in die dost cibos sumendum.
Method: Dissolve the ascorbic acid in the double strength chloroform
water and use this solution to dissolve the ferrous sulphate. Add the
orange syrup and sufficient water to produce 100ml and shake the bottle
thoroughly.
Note:
1. The ferrous ion could undergo oxidation to ferric, an anti-oxidant,
ascorbic acid is therefore included in the formula. The product is
meant for children’s use. It is therefore flavoured with orange syrup.
The preservative and sweetening agent in chloroform water.
25
2.
Paediatric mixtures are usually given undiluted but some contain
ingredients that irritate the stomach or intestine and may cause
vomiting and diarrhoea unless the preparation is well diluted with
water before administration. Paediatric ferrous sulphate solution is an
example of such mixtures. The omission of a direction to dilute well
with water is a serous error.
℞ Potassium Citrate Mixture BP 1988
Synonym: Potassium Citrate Oral Solution
Potassium Citrate
300g
Citric Acid Monohydrate
50g
Lemon Spirit
5ml
Quillaia Tincture
10ml
Syrup
250ml
Chloroform Water D/S
300ml
Water to
1000ml
Send 50ml.
Label. Three teaspoonfuls to be taken at night. Follow the general
dispensing procedure as above. State the following under each preparation
in your practical book.
1. Storage conditions
2. Action and uses.
26
SCHEDULE 4
MIXTURES CONTAINING DIFFUSIBLE SOLIDS
Diffusible solids are insoluble powders that are light and easily wettable.
They readily mix with water and on shaking; they diffuse evenly
throughout the liquid for long enough to ensure uniform distribution in
each dose (such substances are also known as dispersible solids).
Examples of such substances are:
Bismuth Carbonate
Light Kaolin
Light Magnesium Carbonate
Magnesium Oxide
Magnesium Trisilicate
Rhubarb Powder.
General Method of Preparation:
1.
Finely powder the substance using a mortar (if necessary). Mix the
insoluble powders in the mortar. Measure about three quarters of the
vehicle, pour a little portion of it into the mortar containing the
powders and triturate to form a smooth paste, then gradually add the
remainder of the measured vehicle.
2.
Add any liquid ingredients; and rinse the measure and mix well after
each addition.
3.
Rinse the mortar and pestle with successive volumes of the vehicle,
transferring the rinsing into the dispensing bottle.
4.
Add more of the vehicle to produce the prescribed volume and shake
the bottle.
5.
Attach the label.
NOTE: A direction to “Shake the bottle” should be given on the label.
27
PRACTICAL
Dispense the following:
1.
℞ Magnesium Sulphate Mixture BP 1988.
Synonym: Magnesium Sulphate Oral Suspension.
Magnesium sulphate
400g
Light magnesium carbonate
50g
Concentrated peppermint emulsion
25ml.
Double strength chloroform water
300ml.
Water to
1000ml.
Let the mixture be made. Label one tablespoonful to be taken two
and half hour before breakfast.
Send 50ml.
Note:
Follow the general dispensing procedure as stated in your practical
schedule of last week. Follow the method of preparation given above.
Comment on the role of each ingredient in this preparation.
2.
℞ Magnesium Trisilicate and Belladonna Mixture PC.
Magnesium Trisilicate
500mg.
Light Magnesium Carbonate
500mg.
Sodium Bicarbonate
500mg.
Balladonna Tincture
0.5mlo.
Peppermint Water to
10ml.
Make the mixture. Label one tablespoonful to be taken three
times daily after food.
Send 50ml.
Follow the general dispensing procedure. A suitable method of dispensing
the mixture is as follows:
(a) Dissolve the sodium bicarbonate in the vehicle.
28
(b) Rub the magnesium trisilicate and light magnesium carbonate
powders down to a smooth paste in a mortar with the sodium
bicarbonate solution.
(c) Add the belladonna tincture and more vehicle.
(d) Transfer the suspension quantitatively to the dispensing bottle and
make up to volume.
Comment on the role of each ingredient, in this preparation.
3.
℞ Kaolin and Morphine Mixture BP 1988
Synonym: Kaolin and Morphine Oral Suspension.
Light Kaolin
Sodium Bicarbonate
Chloroform and Morphine Tincture
Water to
Send 50ml.
2.0g.
0.5g.
0.4ml.
10ml.
29
SCHEDLE 5
MIXTURES CONTAINING INDIFFUSIBLE SOLIDS
A solid is regarded as indiffusible when it will NOT remain evenly
distributed in the vehicle long enough to ensure uniformity of the
measured dose.
Examples of some common indiffusible substances are as follows:
Acetylsalicylic Acid
Barbiturates e.g. Phenobarbitone
Bismuth Salicylate
Phenacetin
Podophyllum Resin
Prepared Chalk and Aromatic Chalk
Salicylic Acid
Sulphonamides e.g. Succinyl Sulphethiazole, Sulphadimidine.
The viscosity of the medium should be increased to obtain a stable
suspension. Therefore, a suitable suspending agent is added. The amount
of the suspending agent depends upon the volume of the mixture. The two
best suspending agents for general use are:
(a) Compound Tragacanth Powder BP. The quantity used is 2g per
100ml. of mixture (i.e. 2% w/v of the preparation).
(b) Tragacanth Mucilage B.P. The volume used is 1¼ of the volume of
the mixture (i.e. 25 v/v of the preparation)
Method of Preparation using
Compound Tragacanth Powder BP
1. Finely powder the indiffusible substance, add any soluble or diffusible
solids and the compound tragacanth powder and mix intimately.
2. Dissolve any soluble powders in some of the vehicle. Triturate the
insoluble powder in the mortar with the solution.
3. Proceed, following the different stage given under the preparation of
mixtures containing diffusible solids.
30
PRACTICAL
1. ℞
MIXTURE I
Acetylsalicylic Acid
Chloroform Water ad.
300mg
15ml.
Make the mixture. Send 50ml.
Label: t.d.s.
2. ℞
MIXTURE II
Acetylsalicylic Acid
450mg
Compd. Tragacanth Powder
300mg
Chloroform Spirit
0.4ml.
Water to
20ml.
Make the mixture. Send five doses.
Label: t.d.s.
Answer the following questions:
(1)
(2)
Comment on the differences in quality between Mixture I &
Mixture II.
State the role of each ingredient in the three formulations.
31
SCHEDULE 6
PREPARATION OF SYRUPS
Synonyms: Syrup; Oral Liquids; or Oral Solutions.
Syrups are concentrated aqueous solutions of sucrose or other sugars to
which medicaments or flavourings may be added. Glycerin, sorbitol or
other polyhydric alcohols are sometimes added in small amounts to
medicated syrups to retard crystallization of sucrose or to increase the
solubility of other ingredients.
PRACTICAL.
Dispense the following:
℞ Syrup BP
Sucrose
Purified Water sufficient to produce
667g.
1000g.
Make the syrup
Send 50ml.
Method of Preparation (Gravimetric)
1. Weigh the appropriate quantity of sucrose, place it in a porcelain
dish, and add purified water.
2. Next, counter-balance the dish and its content on the scales and note
the total weight.
3. Dissolve the sucrose by heating on a water bath stirring continuously.
4. When the solution is complete allow the dish to cool somewhat
return to the scales and add sufficient boiling purified water to make
up for that lost by evaporation.
5. Finally, if impurities are present, strain the syrup, while still warm,
through fine muslin supported in a funnel into a bottle and shake
occasionally until the contents are quite cold.
32
Answer the following questions:
(1) What will be the effect on the syrup prepared above?
(a) When it is packed in a wet bottle and stored?
(b) When stored either in a warm or a cold place?
Suggest the best storage conditions for syrup BP.
(2) Name the different types of syrups used in pharmacy.
(3) State the different methods of preparing syrups.
Orange Syrup BP
1.
℞ Orange Syrup BP
OrangeTtincture
Syrup, sufficient to produce
Send: 50ml.
2.
60ml.
1000ml.
℞ Ferrous Phosphate Syrup Compound BP
Synonyms: Ferrish’s Food, Farrish’s Syrup; Chemical Food.
Sucrose
Calcium Carbonate
Iron
Cochineal
Potassium Bicarbonate
Sodium Phosphate
Orange-Flower Water of
commerce, undiluted
Phosphoric Acid
Water to
700.0g
3.6g.
4.3g.
3.5g.
1.0g.
1.0g.
50.0ml.
48.0ml
1000.0ml.
Make the syrup. Send 50ml.
Label: One desert spoonful to be taken three times daily.
33
Method of Preparation (Volumetric)
1. Dilute 20ml of the phosphoric acid with 25ml of water, add the
iron and heat gently on a water-bath until the iron has dissolved.
2. Add the solution to the calcium carbonate, the potassium
bicarbonate and the sodium phosphate, previously triturated with
the remainder of the phosphoric acid and 80ml of water.
3. Boil the cochineal with 375ml of water for 15 minutes, cool,
strain, and pass sufficient water through the strainer to produce
800ml.
4. Filter the iron solution into the syrup thus obtained add the orange
flower water, pass sufficient water through the filter to produce
the required volume, mix, allow to stand for at least 8 hours, and
filter if necessary.
5. Pack and label the preparation.
Answer the following questions:
(1) What are the active ingredients of this preparation?
(2) Explain why ferrous (iron) and the phosphoric acid was heated
separately.
(3) What is cochineal and how is the colouring agent sufficiently
extracted according to the BP procedure?
34
SCHEDULE 7
PREPARATION OF ELIXIRS AND LINCTUSES
Synonyms: Elixirs; Elix., Oral Liquids, Oral Solutions.
Elixirs are clear, pleasantly flavoured liquid preparations of potent or
nauseous medicaments. The vehicle may contain a high proportion of
alcohol or other solvent such as glycerin or propylene glycol, sugars, or
other sweetening agents may be present.
1.
Streptomycin Elixir, Paediatric BP 1988
Synonym: Streptomycin Mixture, Paediatric
℞
Sucrose
750.0g.
Streptomycin Sulphate
31.4g.
Sodium Citrate
9.0g,.
Methyl Hydroxybenzoate
1.3g.
Citric Acid
1.0g.
Amaranth Solution
2.0ml.
Purified Water to
1000.0ml.
Send 50ml.
Label: One desert spoonful t.d.s.
Dissolve the methyl hydroxybenzoate in 100ml of water with the aid of
gentle heat, dissolve the sodium citrate, the citric acid add sucrose in the
hot solution and cool. Dissolve the streptomycin sulphate in 100ml of cold
water, and mix the two solutions. Add the amaranth solution and
sufficient water to produce the required volume and mix.
2.
Paracetamol Elixir Paediatric BP
Synonym: Elix. Paracetamol Oral Solutions.
℞
Paracetamol
Alcohol
120mg
0.5ml.
35
Chloroform Spirit
Propylene Glycol
Conc. Raspberry Juice
Amaranth Solution
Invert Syrup
Glycerin to
Send 50ml.
Label: One teaspoonful t.d.s
0.1ml.
0.5ml.
0.125ml.
0.01ml.
1.375ml.
5ml.
Dissolve the paracetamol by shaking with the alcohol, chloroform spirit
and propylene glycol and add the other ingredients.
LINCTUSES:
Synonym: Linct.
Linctuses are viscous liquid preparations usually containing sucrose and
medicinal substances and possessing demulcent, expectorant or sedative
properties. They are usually used for the relief of cough. They are
administered in doses of small volume and should be sipped and swallowed
slowly without the addition of water.
3.
Codeine Linctus BP 1988
℞
Codeine Phosphate
3g.
Lemon Syrup
200ml.
Benzoic Acid Solution
20ml.
Chloroform Spirit
20ml.
Water
20ml
Tartrazine Solution Compound
10ml.
Syrup to
1000ml.
Send 50ml.
Label: One dessertspoonful t.d.s.
Dissolve the codeine in the water and add the other ingredients.
36
SCHEDULE 8
LIQUID PREPARATIONS FOR EXTERNAL USE
PREPARATION OF LOTIONS.
Synonyms: Lotions, Lt.
Lotions are liquid preparations intended for application to the skin for the
treatment of skin diseases or as antiseptics, anti-pruritic or protective.
They are applied without friction on lint or other soft material or dabbed
on the skin. The inclusion of alcohol in a lotion hastens its drying and
accentuates its cooling effect, whilst the inclusion of glycerin keeps the
skin moist for a considerable time; and also promotes adherence of the
residue powder on the skin surface.
Lotions may be classified into:
(a)
Simple solutions (watery lotions).
(b)
Emulsion type lotions; and
(c)
Suspensions (shake lotions) i.e. lotions containing insoluble
substance.
Containers for Lotions
Lotions should be dispensed in coloured fluted bottles in order that they
may be distinguished from preparations intended for internal use.
Labeling:
The container should be labeled, “For external use only” and “shake the
bottle”. The label on a diluted lotion should also state that the lotion
should not be used later than one month after issue for use.
37
1.
℞
Lead Lotion, Evaporating (BP 1988)
Alcohol (95%)
Strong Lead Sub Acetate Solution
Purified Water freshly boiled and cooled to
Send 50ml
Label: Apply to the affected part.
2.
℞
Calamine Lotion, Oily (BP 1988)
Calamine
50g.
Wool Fat
10g.
Arachis Oil
500ml.
Oleic Acid
5ml.
Calcium Hydroxide Solution to 1000ml.
Prepare 50ml
Label: To be used as directed.
125ml.
25ml.
1000ml.
Method of Preparation:
Triturate the calamine with the wool fat, the arachis oil and the oleic acid
previously melted together, transfer to a suitable container, add the
calcium hydroxide solution and shake vigorously. Make up to volume with
more calcium hydroxide solution and shake again.
3.
℞
Sulphur Lotion, Compound (BP 1988)
Precipitated Sulphur
40g.
Alcohol (95%)
60ml.
Glycerin
20ml
Quillaia Tincture
5ml.
Calcium Hydroxide Solution to 1000ml.
Send 50ml
Label: Apply to affected part every night.
Method of Preparation.
Dispense the precipitated sulphr in the alcohol and the glycerin previously
mixed, add the quillain tincture and sufficient of the calcium hydroxide
solution to produce the required volume, and mix.
38
SCHEDULE 9
PREPARATION OF LINIMENTS
Synonyms: Liniments; Lin.
Liniments are liquid or semi-liquid preparation which are intended for
external application and may contain substances possessing analgesic,
rubefacient, soothing or stimulating properties.
Methods of Application
Analgesic and soothing liniments may be applied to the skin on a warmed
flannel or other suitable material, or by means of camel-hair brush.
Stimulating liniments should be applied to the skin with considerable
friction by massaging with the hand. Liniments should not be applied to
broken skin.
Types of Liniments
They may be solutions or emulsions, the method of preparation depending
on the class to which they belong.
The B. P. monograph on liniments and the general recommendations for
containers and labeling in the hand-note should be read carefully. N/B
Liniments are always packed in coloured fluted glass bottles and labeled
“for external use only”. The emulsions are also labeled “Shake the bottle”.
A.
SIMPLE SOLUTIONS
The preparation of this type requires no further explanation.
Vehicle:
1. Alcohol
2. Oil.
39
PRACTICAL
1.
℞ Methyl Salicylate Liniment BP
(Linimentum Methylis Calicylatis; Lin Methyl. Sal.)
Methyl Salicylate
250ml
Arachis Oil to
1000ml
Make the liniment and send 50ml.
Label: To be applied as directed.
Dispense the preparation, pack and label. Note the storage condition.
B.
EMULSIONS
Emulsifying Agents Soaps: Soft Soap (Potassium Oleate)
In certain cases, soap is formed during preparation of the liniment from
alkali and fatty acid (e.g. soap liniment B.P.). Acacia gives a “sticky”
preparation unsuitable for external use and is not suitable as an emulsifying
agent.
PRACTICAL
2.
℞ Soap Liniment, (BP. 1988)
Camphor
40g
Oleic Acid
40g
Alcohol (90%)
700ml
Potassium Hydroxide Solution 140ml
Rosemary Oil
15ml
Purified Water to
1000ml.
Make the liniment and send 25ml
Label: To be applied to the affected parts.
Dissolve the oleic acid in 500ml of the alcohol, and add, with stirring, the
potassium hydroxide solution. Dissolve the camphor and the rosemary oil
in the remainder of the alcohol, mix the two solutions add sufficient of the
water to produce the required volume; mix, allow to stand for not less
than seven days and filter.
40
3.
℞ White Liniment (BP. 1988)
(Linimentum Album; Lin. Alb.)
Synonym: White Embrocation
Ammonium Chloride
12.5g
Water
625.0ml
Turpentine Oil
250.0ml
Oleic Acid
80.0ml
Dilute Ammonia Solution
45.0ml
Make the liniment. Send 50ml.
Label: To be applied as directed.
NOTE:
The B.P. quantities above, allow for just over 1000mls, therefore for
100mls, prepare 1/10 of those quantities. Mix the oleic acid with the
turpentine oil, add the dilute ammonia solution mixed with an equal
volume of the water, previously warmed, and shake. Dissolve the
ammonium chloride in the reminder of the water, add to the emulsion,
and mix.
Pack 50mls and label.
41
SCHEDULE 10
PREPARATION OF COLLODIONS AND PAINTS
1. PAINTS
Synonyms: Pigents, Pig.
Paints are liquid preparations intended for application to the skin or mucus
surfaces. They are usually medicated with substances possessing antiseptic,
astringent, caustic or analgesic properties. Resinous substances such as
benzoin, prepared storex or tolu balsam in ethereal solution are employed
as bases of medicated varnishes.
℞ Magenta Paint (B.P. 1968)
(Pigmentum Magentae, Pig, Magent)
Synonyms: Castellani’s Paint, Pigmentum Tuchsinae
Resorcinol
80g
Phenol
40g
Boric Acid
8g
Magenta
4g
Alcohol (90%)
85ml
Acetone
40ml
Water to
1000ml
Send 25ml. Label: To be used as directed.
Dissolve the magenta in the alcohol and the acetone previously mixed.
Dissolve the boric acid in a portion of water; dissolve the alcohol and the
resorcinol in this solution, add the alcoholic magenta solution and
sufficient water to produce the required volume and mix.
Label – “For external use only”.
42
2. COLLODIONS
These are preparations applied to the skin for the protection of small cuts
and abrasions. Collodions are also used as vehicles for the application of
drugs when prolonged local action is required.
℞ Salicylic Acid Collodion (B.P. 1988).
Salicylic Acid
120g.
Flexible Collodion to 1000ml.
Prepare 25ml
℞ Flexible Collodion (BP 1988)
Pyroxylin
Colophony
Castor Oil
Alcohol (90%)
Solvent Ether, sufficient to produce
Send 25ml.
Label: To be used as directed.
16g
30g
20g
240ml
1000ml.
Immerse the pyroxylin in the alcohol and add the colophony and castor oil,
and finally sufficient solvent either to produce 1000ml. Shake occasionally
until dissolved; allow any deposit of unreacted cotton or of high nitrates of
cellulose to settle; decant the clear solution.
Preparation of Pyroxylin
Pyroxylin is nitrated cellulose obtained by the actions of a mixture of nitric
and sulphuric acids on cotton linters, which have been freed from fatty
matter.
Procedure.
1. Mix 5ml of conc. Nitric acid with 5ml of conc. Sulphuric acid and cool
the mixture at room temperature.
2. Immerse 0.40 of absorbent cotton wool in the mixture, keeping the
latter cool by standing the vessel in cold water.
43
3. Stir well the wool in the mixture for 10 minutes. In order to ensure
even distribution of the acids. Allow to stand for 50 mins. Remove the
nitrated wool, press and wash to remove the acids completely and weigh
the amount required to prepare the flexible collodion.
Storage:
Collodions are stored in small light-resistant, well-closed containers and
labeled:
“For external use only”
Store in a cool place
Highly inflammable
“Keep away from naked flames”
Throat Paints
Throat paints are used for mouth and throat infection; e.g. Compound
Iodine Paint (Mandl’s Paint) for pharyngitis and follicular tonsillitis.
℞ Crystal Violet Paint Compound (BP 1988)
(Pigmentum Iodine Compositum; Pig. Ind. Gp.)
Synonym: Mandl’s Paint.
Potassium Iodide
25.9g
Iodine
12.5g
Alcohol (90%)
40.0ml.
Water
25.0ml.
Peppermint Oil
4.0ml.
Glycerin to
1000.0ml.
Send: 25ml.
Label: The Throat Paint.
NOTES:
(a)
Because of the high viscosity of the vehicle this preparation is best
made entirely in a measure. For the same reason, excess should be
prepared since it is impossible to transfer the entire content of the
measure to a bottle. In this instance, 40ml should be made to
44
avoid approximation, the excess is rather large but the remainder
is usually kept for future use.
(b)
(c)
A glass can or a counter-balanced watch glass and a vulcanite
spatula must be used for weighing the iodine and they should be
washed immediately afterwards.
Care must be taken to avoid spillage during weighing preparation
of the solution. This is because the bench surface can be badly
stained by the dye, iodine.
Method of Preparation:
(a) Put the water into a 50ml conical measure;
(b) Dissolve the Kl, add the iodine and stir until completely dissolved
(c) In a 10ml conical measure, dissolve 0.2ml of peppermint oil in 2ml of
alcohol (90%). Using a pipette transfer 1.76ml to the iodine solution
and mix well.
(d) Make up to volume with glycerol and mix thoroughly;
(e) By difference, transfer 25ml. to the container. Container and storage
– see the BP under paints.
Labels
“Store in a cool place” – because iodine is volatile “Shake the bottle” –
because some of the oil separates on storage. “Not to be swallowed in
large amounts” – alternatively this advice can be given verbally to the
patient, with an explanation.
45
SCHEDULE 11
PREPARATION OF GARGLES, MOUTHWASHES
AND EAR DROPS
A. GARGLES
Synonym: Gargarismaye, Garg.
A gargle is an aqueous solution, usually in a concentrated form, intended
for use, after dilution, as a prophylactic or in the treatment of an infection
of the throat. The particular method of using a gargle intended in brings it
into intimate contact with the membranous lining throat. It is not intended
to act as a protective covering to the membrane, and therefore oily
substances requiring suspending agents, and drugs of a mucilaginous nature
should not be used.
1.
Potassium Chlorate and Phenol Gargle (BP 1988)
(Gargarisms Potassium Chloratis at Phenolis)
Potassium Chlorate
30.0g
Sulphon Blue (Blue BPS food
Grade of commerce)
0.009g
Liquefied Phenol
15.0ml.
Purified Water to
1000ml.
Send 50mls.
Label: One tablespoonful to be added to half a tumbler-full of
warm water before use.
“Not to be swallowed in large amounts”. A stock solution of the dye
containing 50mg/100ml. should be prepared. 2ml of this stock solution
contains approximately 1mg of sulphon blue required in the preparation.
Method:
(a) Dissolve the potassium chlorate in about 75ml of warm water.
46
(b) Cool before adding the liquefied phenol.
Note: Liquefied phenol is very caustic and measurement in a
pipette by mouth must not be attempted.
(c) Add the dye solution, filter if necessary, and make up to volume.
Containers
A white fluted bottle is recommended for gargles unless they are to be
swallowed hut since this gargle is to be protected from light, a light
resistant bottle is used.
Label: Label in red. Add “Not to be taken” (and “shake the bottle” if
appropriate).
B. MOUTH-WASHES
Synonym – Collutaria: Collut.
Mouth – washes are usually aqueous solutions, in a concentrated form, of
substances with antiseptic, local analgesic or astringent properties.
2.
Zinc Sulphate and Zinc Chloride Mouth-Wash (BP 1988)
(Collutoruim Zinc Sulphatis et Zinc Chloridi)
Collut. Zinc Sulph. Et Zinc Chlori
Zincl Sulphate
20.0g
Zinc Chloride
10.0g
Dilute Hydrochloric Acid
10.0ml
Compound Tartrazine Solution 10.0ml
Chloroform Water to
1000ml
Send 50ml.
Label: To be diluted with two time its volume of warm water
before use.
Does this direction for use correspond with that of the BP? If not, what do
you do?
47
Method:
(a) Zinc chloride is very deliquescent. Crush a stick quickly in a mortar
weigh the required amount and immediately return the excess to the
bottle and close tightly.
(b) Proceed as for gargles.
Container
White fluted screw-capped bottle.
Label: The print on the label should be in red. Add “Not to be taken”
(“Shake the bottle” if required) so that the product is clearly distinguishable
from a preparation. Intended for internal use.
C. EAR DROPS
Synonyms – Auristillae, Aurist.
Ear-drops are solutions, or suspensions, or suspensions of medicaments in
water, glycerin, diluted alcohol, propylene glycol, or other suitable
vehicle, which are intended for instillation into the ear.
3.
Sodium Bicarbonate Ear-Drops (B.P. 1988)
Sodium Bicarbonate
Glycerin
Purified Water, freshly boiled and cooled to
Label: Three or four drops to be put into the affected
day.
5.0g
30.0ml
100.0ml
ear three times a
Method:
Dissolve the sodium bicarbonate in about 6.0ml of the water, add the
glycerin and sufficient of the water to produce the required volume and
mix.
Note: The ear-drops should be recently prepared.
Containers and Labeling
See the B.P. and the general recommendation in the manual.
48
SCHEDULE 12
PREPARATION OF INHALATIONS AND NASAL
DROPS
Inhalations are liquid preparations containing volatile ingredients for the
medication of the respiratory tract. The ingredients may be volatile at
room temperature in which case they may be inhaled from an absorbent
pad on which the inhalation has been placed, or they may require
volatilization by adding the inhalation to hot (not boiling) water and the
vapour inhaled for five to ten minutes.
Volatile oils and terpene derivatives are commonly prescribed ingredients
and they must NOT be emulsified with gums or suspended with
compound powder of tragacanth.
Container – A white flutted bottle.
Label:
(1) “Shake the bottle” if insoluble ingredients are ;present
(2) “Not to be taken”
(3) The B.N.F. directs that unless otherwise required the wards “Add one
teaspoonful to a pint of hot, not boiling water and inhale the vapour” shall
be written on the label.
PRACTICAL
℞
Menthol
2%
Thymol
1.5%
Compound Tincture of Benzoin to
25ml.
Send 25ml.
Make the inhalation
Label: To be used as directed.
Note: No dispersion agent is necessary in this product.
1.
49
Method:
(1) Measure about 20mls of compound tincture of benzoin
(2) Weigh the menthol, add to the inhalation and stir until dissolved
(3) Repeat with the thymol.
(4) Add sufficient compound tincture of benzoin to adjust the final volume
to 25mls.
Pack into a ribbed bottle, label and polish.
℞
Menthol and Eucalyptus Inhalation (B.P. 1988)
Menthol
2%
Eucalyptus Oil
10%
Light Magnesium Carbonate
7%
Water to
50ml.
Send 50ml.
Label: Add one teaspoonful to a pint of hot, not boiling water and
inhale the vapour.
Note: As menthol and eucalyptus oil are immiscible with water. Light
magnesium carbonate must be added.
Method:
(a) Measure the oil of eucalyptus and transfer it to a glass mortar.
(b) Weigh the menthol, add to the oil and stir with a glass pestle until
dissolved.
(c) Weigh the light magnesium carbonate and carefully “float” it on to the
surface of the oil. Triturate gently with the glass pestle until a smooth
cream is obtained.
(d) Gradually incorporate water, adding initially about the same volume
of ingredients in the mortar.
(e) Transfer to a measure, wash the mortar with further quantities of
water adding the washings to the measure until 25mls is obtained.
Questions:
(1) Which is the alcoholic ingredient in preparation No.1 and what is its
function in the product?
(2) What is the function of light magnesium carbonate in product No.2
and is there any alcoholic ingredient in the preparation?
50
NASAL DROPS
These are solutions of drugs possessing antiseptic, local analgesic or
vasoconstrictor properties. They are usually simple solutions of
medicaments in water, diluted alcohol or glycerin and are intended for
instillation into the nostrils for their local effect.
Oily liquids (e.g. light liquid paraffin) should not be used as vehicles for
nasal drops.
Container – Nasal drops should be dispensed in coloured fluted bottles
with dropper.
Label: The label should include the instructions “NOT TO BE TAKEN”
or “FOR USE ONLY IN THE NOSE” and “STORE IN A COOL PLACE”.
PRACTICAL
3. ℞ Ephedrine Nasal Drops (BP 1988)
Ephedrine Hydrochloride
0.5%
Chlorbutol
0.5%
Sodium Chloride
0.5%
Water to
20ml.
Send 20ml.
Label: Two drops to be placed in each nostril as directed.
Method
(1) Heat about 15mls of water in a conical flask to about 60oC.
(2) Weigh and add the chlorbutol to this warm water in the conical flask,
close by inserting a stopper and shake vigorously until it has completely
dissolved.
(3) Dissolve the ephedrine hydrochloride and sodium chloride in the warm
solution.
(4) Cool, filter and make up to volume through the filter.
Questions:
1. Why are oily liquids not used as vehicles for nasal drops?
2. Why is ephedrine nasal drops not recommended to be used
repeatedly?
51
SCHEDULE 13
PREPARATION OF ENEMAS AND IRRIGATIONS
ENEMAS
Enemas are solutions, suspensions or oil-in-water “emulsions” of
medicaments intended for rectal administration. Enemas are given for
their anthelmintic, anti-inflammatory, nutritive, purgative or sedative
effects or for X-ray, examination of the lower bowel.
There are two types:
(a) Retention enemas and
(b) Evacuant enemas
The volume given varies according to the type of enema. Retention
enemas do not normally exceed 100ml in volume while evacuant enemas
may be as much as 2 litres. Such large volume enemas should be warmed
to body temperature before administration in order to avoid discomfort to
the patient. This is achieved by standing the container in warm water
before use.
PRACTICAL
1. ℞
Paraldehyde Solution
Sodium Chloride Solution (0.9% w/v) to
Send 50ml.
Label: To be administered rectally as directed.
10ml.
100ml.
Method:
(1) Weigh the sodium chloride and dissolve it in a suitable volume of
water to obtain a 0.9% solution.
(2) Filter the normal saline solution using either a filter paper or cotton
wool.
52
NOTE: Usually, a clarify grade sintered glass or membrane filter is used,
paraldehyde is more soluble in cold than warm water therefore to aid its
solution cool the sodium chloride solution under a running tap.
(3) Put the paraldehyde in the bottle, adjust to volume with the vehicle
and shake vigorously until solution is complete.
Container: Coloured, fluted, screw-capped, glass bottles.
Label: Red label.
“Not to be taken” or for rectal use only”
“Store in a cool place in complete darkness”
Expiry Date: Discard after two days”.
2. ℞ Castor Oil
20%
Starch
2.5%
Water to
100ml.
Make the enema.
Label: The enema. To be used at bed time as directed
Note: (The dose of this enema is usually 300ml.)
METHOD:
1. Triturate the starch is a mortar with about 20ml. of water to make
a thin smooth paste. Transfer to a measure and add sufficient
water to produce 80mls.
2. Transfer to a beaker and heat over a Bunsen with frequent
agitation until the contents of the flask boil, when the starch will
gelatinize and form a mucilage.
3. Remove from the heat and cool the contents of the beaker under a
stream of cold water, rotating constantly. (This prevents
formation of a “skin”).
4. Adjust the volume to 80mls. with water, add the castor oil mix by
vigorous stirring and transfer to a bottle and label.
Container: - Coloured, fluted, glass bottles.
Label: “Warm to body temperature before use”
53
Red label
“Not to be taken”
Note: The description “emulsion” is frequently applied to suspension of oil
in starch mucilage. Starch mucilage is not a true emulsifying agentproducts made with it are really suspensions of large oil globules which are
prevented from coalescing by the high viscosity of the starch by the high
viscosity of the starch mucilage.
Questions:
1. What type of enema is preparation No.1, and why is it not
essential to warm this solution before administration?
2. What type of enema is preparation No.2?
IRRIGATIONS
Irrigations are aqueous solutions used as venial or urethral douches. They
may have soothing, antiseptic or astringent action on the mucous
membranes.
They are generally required to be dissolved or diluted before use at body
temperature.
Container: White, fluted screw-capped bottle.
Label: Printing in red.
“Not to be taken”
To be warmed to body temperature before use.
PRACTICAL
3. ℞ Send 100mls of a 1.0% solution of zinc sulphate. Label with
directions for preparing half of a pint of a vaginal douche containing 1% of
zinc sulphate.
54
LATIN TERMS USED IN PRESCRIPTIONS
(Cooper and Guns Dispensing for Pharmaceutical Students 19th Edition)
(pp.720-723).
Traditionally prescriptions are written in Latin and consist of the following
parts. A heading which is the sign Rx, a formula, directions to the
dispenser, labeling instructions, the patients name and the prescriber’s
name. Prescriptions are usually dated. In recent years physicians have
tended to write their prescriptions in English or with very abbreviated
Latin instructions. Understanding of the terms used is best obtained by
practice on prescriptions, referring where necessary of the book listed
above or other sources. A brief list is given below:
LATIN TERM
Ante cibum
Ante jentaculum
ana
adde
amplus (a, um)
ante
application
aqua
aquae adauris
auristillae
bis
bis in die
calidus (a. um)
capiat
capsule
cibus
cochleare
cochleare amplum
“
“
“ medium)
“ modicum)
“ parvum)
ABBREVIATION
a.c.
a.j.
a.a.
add
amp.
applic.
aq.
aq. ad.
aur.
aorist
b.
b.i.d.
calin.
cap
cap.
cib.
cock.
amp
mag.
med.
min.
parv.
TRANSLATION
before food
before breakfast
of each
add
full large
before
an application
water
water up to
the ear
ear-drops
twice
twice a day
warm or hot
let him take
a capsule
food
Spoonful
a tablespoonful
a dessertspoonful
a teaspoonful
55
collutarium
collyrium
comperais
cremor
de die
diebus alternaia
dolere urgente
duplex
emeticum
emplastrium
enema
ex aqua
fiat (fiant)
fiat mistura
fist secundum artem
flavus
gargarisma
gultae
hera somni
haustus
inter nibos
infusum
infricetur
injectio
insufflatio
irrigation
liquor
lotio
mane
more dicto
more dicto utendus
misture
mitte
molls.
nocte
nocte maneque
nomen proprium
naristillae
nebular
collut.
a mouth wash
collyr.
an eye lotion
conspers.
a dusting powder
crem.
a cream
d.d.
daily
diab altern.
every other day
dol. urg.
when the pain is severe
dup.
Double
emet.
an emetic
emp.
a plaster
enem.
an enema
ax. aq.
in water
f.f.; ft.
let it (then) be made
f.m. or ft. mist. let a mixture be made
f.a.a. let it be made according to art.
flav.
yellow
garg.
a gargle
ftt.
drops
h.s
at bed time
haust.
a draught
i.c.
between meals
inf.
an infusion
infric.
let it be rubbed in
inj.
an injection
insuff.
an insufflation
irrig.
an irrigation
liq.
a solution
lot.
a lotion
m.
in the morning
m.d.
as directed
m.d.u.
to be used as directed
mist.
a mixture
mitt.
send
moll.
soft
n.
at night
n.et m.
night and morning
n.n. (NP)
the proper name
narist
nasal drops
neb.
a spray
56
omni mane
omni nocte
oculentum
oleum
parti affecta applicandus(a.um)
post cibum
pro re nata
pas ta
pessus
pigmentum
pulvis
quarter die
quartum sufficiat
quarta quaque hora
recipe
sumendus
si opus sit
signa
solvella
statim
o.m.
every morning
o.n.
every night
oculent
an eye ointment
ol.
oil
n.a.a. to be applied to the affected part.
p.c.
after food
p.r.n. occasionally, when required
past.
a paste
pess.
a possary
pig.
a paint
pulv.
a powder
q.d.
four times a day
q.s.
sufficient
q.q.h.
every fourth hour
Rx.
take
s.
to be taken
s.n.s.
if necessary
sin.
label
solv.
solution-tables
stat.
immediately.
A more comprehensive list of Latin terms phrases that you may find in
prescriptions or dispensing practice.
S/N.
1.
2.`
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
LATIN NAME,
TERM OR PHRASE
Quantum sufficiat
ad
ana
auristillae
collutorium
collyrium
quttae
liquor
lotio
mistura
naristillae
nebula
oculentum
pigmentum
pulvis
ABREVIATIONS
q.a.
ad
a.a.
auristill
collut.
collyr.
qtt.
liq.
lot.
m., mist.
narist
neb.
oculent.
pigm.
pulv.
ENGLISH NAME OR
MEANING
as much as sufficient
up to, sufficient to produce
of each
ear drops
a mouth wash
an eye lotion
drops
a solution
a lotion
a mixture
nasal drops
a spray solution
an eye ointment
a paint
a powder
57
16.
17.
18.
19.
20.
21.
22.
23.
24.
25.
26.
27.
28.
29.
30.
31.
32.
33.
34.
35.
36.
37.
38.
39.
40.
41.
42.
43.
44.
45.
46.
47.
48.
49.
50.
51.
52.
53.
54.
55.
56.
57.
solvellas
trochiscus
unguentum
fiat
misce fiat mistura
mitte
signa
semel in die
bis in die or bis die
ter in die or ter die
quarter in die or quarter die
bis tar ve in die
prima mane
mane
omni mane
vespere
nocte
hora decubitus, hora somni
nocte maneque
mane sequenti
jentaculum
prandium
omni hora or quaque hora
ante cibos
ante cibum
post cibos, post cibum
more dicto, modo dicto.
pro re nata
si. opus sit
statim
ex aqua
dexter
parti arfectae applicandus
sinister
unus
duo
decem
undecim
duo decim
viginti
unus et viginti
more dicto utendus
solv.
solution tablets
troch
a lozenge
uno.
an ointment
ft.
let(it) be made or let (them) be made.
m.ft.m.
mix to make a mixture
mitt.
send
sig.
Label
sem. In die
once a day
b.i.d., b.d.
twice a day
t.i.d., t.d.
three times a day
q.i.d. or q.d.
four times a day
b.t.i.d.
two or three times a day
prim. m.
early in the morning
m.
in the morning
o.m.
every morning
vesp
in the evening
n.
at night
n.d., h.s.
at bed time
n.m.
night and morning
m.seq.
the following morning
jentac.
Breakfast
prand.
Dinner
o.h. or q.q.h.
every hour
a.c.
before meals
a.c.
before food
p.c.
after food
m.d.
as directed
p.r.n.
occasionally
s.o.s
when required or when necessary
stat.
immediately or at once
ex. aq.
with water
dext.
Right
p.a.a
to be applied to the affected part
sinist.
Left
1
one
II
two
x
ten
xi
eleven
xii
twelve
xx
twenty
xxi
twenty-one
m.d.u.
to be used as directed
58
300 LEVEL
59
LIQUID EMULSIONS
An emulsion consists of two liquid phases, one of which is finely
subdivided and dispersed in the other, the system being stabilized by the
presence of an emulsifying agent. Emulsions intended for oral
administration should be of o/w (oil-in-water) type. For container
labeling and storage requirements consult, B.P. 1988, pages 10 (or 616)
and 717, and P.C. (11th ed.) pp. 630 – 632.
EXERCISES ON O/W TYPE EMUSLIONS
(A) O/W Emulsions – Based on Acacia and Methyl Cellulose.
Oil-in-water emulsions which are prepared in bulk must always be
preserved using a suitable, non-toxic preservative, methyl paraben and/or
propyl paraben are suitable for most emulsions, but care must be taken to
ensure that the preservation is compatible with the ingredients of the
emulsion. Emusions which are intended to be used within a fortnight of
preparation need not be preserved, but the use of chloroform water B.P.
is to be recommended for these small quantities. The amounts of the
parabens to be used in large scale manufacture will be found in your
lecture notes.
Exercise 1:
℞
Cod Liver Oil
50ml.
Water to
100ml.
Make an Emulsion.
Send 50ml. 10ml. to be taken twice a day.
Notes:
1. For preparing an emulsion using gum acacia powder as the
emulsifying agent, it is necessary to make a concentrated primary
emulsion first which is then diluted to the required volume.
2. Cod liver oil is a fixed oil. The ratio of the oil, water, emulgent
(gum acacia powder) for the primary emulsion of any fixed oil is
4:2:1 (in exceptional cases, e.g., castor oil and liquid paraffin, a
more stable emulsion is formed if 3:2:1 ratio is used).
3. Calibrate the bottle first and make up the volume in the bottle.
60
Dry Gum Method:
1. Weigh the required quantity of gum acacia powder in a dry
mortar.
2. Measure the oil in a dry measure, transfer into the mortar and
triturate with the gum lightly.
3. Measure the calculated quantity of water in a clean measure and
add all at a time to the content of the mortar and triturate until a
thick, white “clicking” primary emulsion is formed.
4. Dilute with some more quantity of water and transfer into the
bottle. Add sufficient water to make up the volume.
Wet Gum Method:
This method may be used when a large quantity of emulsion is prepared.
1. Some as dry gum method.
2. Measure the water, transfer into the mortar and triturate with the
gum to form a mucilage.
3. Measure the oil and add small quantity at a time to the content of
the mortar, and triturate. This is repeated until the whole quantity
of the oil is mixed.
4. Same as dry gum method.
Exercise 2:
I.
(Tincture of Quillaia
(Mucilage of Acacia
(2% Mucilage of Methyl Cellulose
II.
0.5ml.
6ml.
30ml.
Cod Liver Oil
50ml.
Water, purified to
100ml.
Prepare an emulsion. Send 50ml. Label for a hospital ward.
METHOD:
Mix I in a calibrated bottle. Add II in 3 to 4 portions. Shake vigorously
after each addition for about 30 seconds. Make up the volume with water
and shake well.
61
Note: Quillaia root contain saponin, a surfactant, which facilitates
emulsification. Compare the stability of the two emulsions prepared in
exercises 1 and 2.
Exercise 3:
Liquid Paraffin
50ml.
Orange Syrup
20ml.
Water to
100ml.
Prepare an emulsion. Send 50ml. 5ml. b.i.d.
Note: Use 3:2:1 ratio for the primary emulsion.
Exercise 4:
I.
(Tincture of Quillaia
(Mucilage of Acacia
(2% Mucilage of Methyl Cellulose
II.
III.
0.5ml.
6ml.
30ml.
Liquid Paraffin
50ml.
Cinnamon Water to
100ml.
Make an emulsion. Send 50ml. Label for a ward.
METHOD: (See Exercise 2).
1. Pass half of the emulsion through a hand homogenizer and
compare the globule sizes of the dispersed phase with those of the
other half.
Exercise 5:
Repeat exercise 3 using 30% oil ricine (castor oil) in place of liquid
paraffin.
Exercise 6:
Repeat exercise 4 using castor oil in place of liquid paraffin, label for a
hospital ward, find the type of the above two emulsions by dilution and
staining taste.
62
Exercise 7:
Arachis Oil
3ml
Phenolphthalein
50mg.
Sodium Citrate
200mg.
Water to
10ml.
Make an emulsion. Label as such. Send 50ml.
(B) O/W Emulsions Based on Monovalent Soaps:
Exercise 8:
℞
I.
(Triethanolamine
(Oleic Acid
II.
III.
0.5g.
2.0g.
Benzyl Benzoate
25.0ml.
Water
25.0ml.
Water to
100ml.
Make an emulsion. Send 50ml. To be used as directed.
METHOD:
Mix I, add II and shake.
Add III and shake intensively.
Mix more water by shaking to make up to volume.
Find the type of the above emulsion by dilution and staining tests.
Exercise 9:
℞
I.
(Oleic Acid
(Arachis Oil
II.
1
74
Liquid Ammonia (10%)
25
Make an emulsion. Send 50ml. To be used as directed.
METHOD:
Mix I and II and shake vigorously.
63
Arachis oil may not contain the required quantity of free fatty acids hence
the addition of an extra quantity of oleic acids. However, if the oil is of
good quality emulsion will form without the addition of oleic acid.
(C) Emulsions Based on Multivalent Soaps and Cholesterol
Compounds:
Exercise 10:
℞
Oleic Acid
1%
Arachis Oil
50%
Lime Water to 100%
Send 50ml.
METHOD:
Mix all the three ingredients in a bottle by shaking vigorously.
Exercise 11:
℞
Wool Fat
6 parts
Liquid Paraffin
50 parts
Water
44 parts
Make an emulsion. Label as such. Send 50ml.
METHOD:
Melt the wool fat over a water bath; add liquid paraffin and transfer into a
dry bottle. Add water of same temperature as the water bath in three to
four portions, with intensive shaking.
Note:
1. Wool fat can emulsify about half its own weight of water; when mixed
with fats, e.g. liquid paraffin, it can emulsify several times its own weight
of an aqueous liquid. The resultant emulsions are of the water-in-oil type.
2. Wool fat consists mainly of fatty acid esters of cholesterol, lanesterol
and fatty alcohols, which exert emulsifying property.
64
Exercise 12:
Wool Alcohols
3%
Liquid Paraffin
52%
Water
45%
Send 50ml.
Follow the same method as described under exercise 11. Wool alcohols
contain about 30 – 35 percent of cholesterol and 10 – 13 percent of isocholesterol. A portion of this emulsions will be passed through a hand
homogenizer and both the non-homogenized and the homogenized
emulsion, place on glass slides, will be mounted on microscope. Students
are required to see the sizes of the disperse phase globules on these and
comment.
Exercise 13:
Cholesterol
1%
Liquid Paraffin
54%
Water
45%
Send 50ml. of the emulsion.
METHOD:
Dissolve cholesterol in liquid paraffin in a flask placed over a water bath
and cool. Transfer to a bottle and add water of same temperature and the
bath in portions with intensive shaking. Find the type of the above three
emulsions by dilution and staining tests.
65
SEMI-SOLID PREPARATIONS
(OINTMENTS, CREAMS AND PASTES)
Most of these products are intended for external application to the skin.
Ointments are semi-solid preparations usually containing a medicament
dissolved or dispersed in fatty bases. Water-soluble ointments may be
prepared using a base consisting of mixtures of polyethylene glycols
(Macrogols). Emulsifying agents are incorporated in some anhydrous fatty
bases to make them miscible with exudates and more easily removable
from the skin by washing.
Creams are semi-solid emulsions which may be of an oil-in-water (o/w,
aqueous creams) or water-in-oil type (w/o, oily creams); o/w emulsifying
agents used in creams include sulphated alcohols, quaternary ammonium
compounds, monovalent soaps and non-ionic surface active agents, often
in combination with fatty alcohols or fatty acids.
Oily creams are prepared with wool alcohols beeswax, calcium soaps,
certain sorbitan esters and other emulsifying agents. Preservation of
creams is often a problem, particularly the aqueous type, as they are often
attacked by moulds and other microorganisms. For this reason, a
preservative is usually included in o/w creams. Certain medicaments are
also incompatible with some emulsifying systems.
Pastes are similar to ointments but often contain a very high proportion of
powdered medicaments.
Note: For a complete description of these products and the relevant
container, storage and labeling requirements, students are advised to read
the general monographs on pages 232 and 614 of P.C. 1979 and pages 10
(or 616), 650 and 704 of B.P. 1988. Note also the remarks on ointments
used in tropical countries on page 8138 of the B.P. 1973.
One method of classifying ointments has been given to you in your course
work. In your laboratory notebook, at the end of each write-up, state to
which class the ointment or cream belongs.
It is necessary to make a reasonable allowance for unavoidable losses by
preparing a slight excess. For example, if you are required to send 25g, a
66
reasonable amount to prepare would be 30g out of which 25g is
transferred to the jar.
(A)
Ointment Bases of Lipoid Character
(Fatty or Hydrocarbon Bases):
Send 25g each of the following ointment bases:
Ex. 1 Simple Ointment B.P.
Ex. 2 Paraffin Ointment P.C.
Ex. 3 Wool Alcohols Ointment P.C.
(B)
Medicated Ointments of Lipoid Character:
Send 25g each of the following:
Ex. 4 Zinc Ointment B.P.
Ex. 5 Calamine Ointment P.C.
Ex. 6 Calamine and Coal Tar Ointment P.C.
Ex. 7 Methyl Salicylate Ointment P.C.
(C)
Ointment with Polyethylene Glycol (Macrogol) Bases:
Send 25g of each of the following:
Ex. 8 Macrogol Ointment P.C.
Ex. 9 Sulphur, finely sifted
Macrogol Ointment P.C. to
Label as appropriate.
1.0g.
30.0g.
Note: The high degree of solubility of macrogol bases in water preclude
the addition of aqueous solutions much in excess of 5% of the total
formula.
The following base composition is recommended when larger amounts of
aqueous solution are to be incorporated;
Macrogol 4000
47.5
Macrogol 400
47.5
Cetyl Alcohol
5.0
67
(D)
O/W Cream Bases:
Send 25g of the following:
Ex. 10 Emulsifying Ointment B.P.
Emulsifying Wax
300g.
White Soft Paraffin
500g.
Liquid Paraffin
200g.
Label as such.
METHOD:
Melt together and stir until cold.
Note: This ointment is ANIONIC in character due to the presence of
emulsifying wax which contains sodium lauryl sulphate as one of its
ingredients. As such, this is lipoid in character but on addition of water it
forms an o/w cream base (see following exercise).
Ex. 11: Aqueous Cream B.P.
Emulsifying Ointment
Chlorocresol
Purified Water
Label as such. Send 25g.
(Hydrous Emulsifying Ointment)
300g.
1g.
699g.
This is an o/w emulsion of paraffins and it is used as a water-miscible
cream base. It is preserved with chlorocresol. The emulsion is prepared by
melting the fatty ingredients at about 60oC, adding the requisite amount of
aqueous phase heated to the same temperature and stirring the mixture
until it is cold. The quality of the emulsion depends largely on the degree
of shearing applied at a critical temperature when the emulsion begins to
solidify.
The chlorocresol cannot be directly weighed and must be obtained by
trituration. The emulsifying ointment required should be obtained by
trituration. The emulsifying ointment required should be obtained from
the preparation made in Ex.10 above.
68
METHOD:
(i)
Dissolve the chlorocresol in an appropriate volume of purified
water over a hot water at 60oC.
(ii)
Weigh and melt the emulsifying ointment in a tarred porcelain
dish over the same water bath.
(iii)
Mix the chlorocresol solution with the molten fatty materials at
the same temperature. Add more purified water, warmed to
60oC, to make the product up to the final weight.
(iv)
Stir until cold (over a cold water bath, if necessary) using a glass
rod or a glass pestle as stirrer.
Note: As the cream is ANIONIC in character, this base is incompatible
with cationic drugs, e.g. cetrimide, antihistamines, acridines etc.
Ex. 12: Cetrimide Emulsifying Ointment B.P.
White Soft Paraffin
500g.
Cetostearyl Alcohol
270g.
Liquid Paraffin
200g.
Cetrimide
30g.
NOTE: This ointment is CATIONIC in character due to the presence of
cetrimide. This is also lipoid in character.
Ex. 13: Cetrimide Cream B.P.
Cetrimide
Cetostearyl Alcohol
Liquid Paraffin
Purified Water freshly boiled and cooled to
Send 25g.
Label as appropriate.
5g.
50g.
500g.
1000g.
METHOD:
Melt the cetostearyl alcohol over a heated water bath, add the liquid
paraffin, and warm; dissolve the cetrimide in the water at the same
temperature and add to the melted oily mixture, stirring gently (over a
cold water bath, if necessary) until cold.
69
NOTE: This cream can also be prepared by mixing 30% Cetrimide
Emulsifying Wax P.C. with 70% purified water.
Ex. 14: Cetomacroscol Emulsifying Ointment B.P.
White Soft Paraffin
500g.
Cetemacrogol Emulsifying Wax 300g.
Liquid Paraffin
200g.
Send 25g. Label as such.
Melt together and stir until cold.
NOTE: This is non-ionic in character. Like those prepared in Ex.10 and
12, this can also be converted to an o/w cream base on the addition of
water.
Ex. 15: Cetomacrogol Cream B.P. (using formula A of the B.P.)
Cetomacrogol Emulsifying Ointment
300g.
Chlorocresol
1g.
Purified water freshly boiled and cooled to
1000g.
Send 25g. Label appropriately.
METHOD:
Same as in Ex. 11 and the Cetomacrogol Emulsifying Ointment is obtained
from Ex. 14 above.
NOTE: To help to prevent production of a granular preparation, the
temperature of the melted ingredients should not exceed 65oC and the
Chlorocresol should be dissolved in not less than 50ml of warm water
before adding to the melted emulsifying bases.
NOTE: This base is non-ionic in character and compatible with most ionic
drugs.
QUESTION:
Explain why a preservative (chlorocresol) is included in the aqueous cream
and Cetomacrogol Cream but not in Cetrimide Cream.
70
Ex. 16: Send 25g of the following cream base.
Stearic Acid
10
Cetyl Alcohol
5
Glycerin
10
Light Mineral Oil
20
Triethanolamine
2
Water to
100
To be used as directed.
Ex. 17: Vanishing Cream Base.
Stearic Acid
15.0
White Beeswax
2.0
Triethanolamine
8.0
Propylene Glycol
1.5
Water
65.5
Send 25g. To be used as directed.
(E)
Medicated O/W Creams
Ex. 18: Send 25g of Calamine Cream, Aqueous P.C.
Label appropriately.
Ex. 19: ℞
Sulphur
2.0
Phenol
0.5
Cetyl Alcohol
8.0
White Beeswax
0.5
Propylene Glycol
5.0
Sodium Lauryl Sulphate
1.0
Water to
80.0
Label. Apply to scalp as directed. Dispense 25g.
71
1. SHAVING PREPARATIONS
A. LATHER TYPE
A shaving product is a preparation, which softens the beard sufficiently and
provides lubricity so that the razor can glide and cut easily along the face.
A shaving product should not be irritant to the face and should retain its
moisture during application.
Coconut oil possesses short-chain irritant free fatty acids. In some
formulations therefore, olive oil is included to reduce the irritant effect of
coconut oil. The hydroxides react with the stearic acid and free fatty acids
to form soap. Sodium hydroxide form hard soap while potassium
hydroxide forms soft soap. This helps to give the final cream consistency.
1. ℞ Stearic Acid
Coconut Oil
Glycerol
Potassium Hydroxide
Sodium Hydroxide
Water ad
Send 25g.
35g.
10g
10g
6.8g
1.6g
100g.
METHOD OF PREPARATIONS:
1. Melt ¼ of the stearic acid together with the coconut oil on a water bath.
2. Dissolve the required quantities of KOH and NaOH in a mixture of
water and glycerol. Heat the solution and add to the molten oils.
3. After complete saponification add the remaining amount of stearic acid
in melted form, to the formed soap and triturate in a mortar.
4. Dispense 25g of the product in a cream jar.
B. BRUSHLESS TYPE SHAVING CREAM
At the time of their introduction, brushless shaving creams were thought
to be quite revolutionary. They undoubtedly suit some dry skins and those
that are abnormally sensitive to soap. In general brushless creams have a
more pronounced lubrication action than lather creams, and can be
distinguished from ordinary vanishing creams, which they otherwise
72
resemble, by their higher oil content. The addition of wetting agents to
these creams is a source of skin irritation and is not to be recommended.
The following formula provides a useful starting point for individual
experimentation in that it contains a humectant and lubricant in a relative
non-greasy, self-emulsifying base.
1. ℞
Glyceryl Monostearate
Spermaceti
Olive Oil
Glycerin
Water
Preservative
Perfume
Make 25g.
12%
4.5%
2.5%
7.0%
73.5%
0.1%
0.1%
METHOD OF PREPARATION:
Melt the glyceryl monostearate with the spermaceti and olive oil at 75oC.
Heat the glycerin, water and preservative together at the same
temperature, mix and stir until a homogenous product is obtained. The
perfume is added 45oC whilst the product is still soft.
2. AFTER-SHAVE PREPARATIONS
After-shave preparations are intended to relieve the felling of discomfort
caused by shaving. They should refresh and cool the skin, sooth minor
irritation and give a feel of well-being. After shave lotions also act as mild
astringent and neutralizing agent to the soap left on the skin.
1. ℞
AFTER-SHAVE LOTION
Stearic Acid
3g.
Cetyl Alcohol
0.5g.
Glycerin
2g.
Potassium Hydroxide 0.2g.
Ethyl Alcohol
5ml
Water to
100ml.
Send 50ml.
73
METHOD OF PREPARATION:
1. Melt the required quantities of stearic acid and cetyl alcohol on a
water bath.
2. Dissolve the potassium hydroxide in about 6ml of water; add the
glycerin and heat gently to the same temperature of the melted oils.
3. Mix the above two liquid preparations with gentle stirring until
saponification is achieved.
4. Add to the mixture, the required amount of the 20% mucilage of
tragacanth and the remaining portion of water with continuous
stirring.
5. Allow the preparation to cool and add the required volume of ethyl
alcohol.
Unfortunately, it has recently been shown that after-shave lotions are not
all soothing, or even act to leave behind a refreshing odour. A consumer
organization known as ‘which’ carried out a survey in U.K. in 1961 and
found that of 45 products tested, the pH varied between 3.7 and 8.8 and
the alcohol content was between 40 – 75%. In general, after-shave lotions
resemble the skin tonics used by women. A typical formula is the
following:
2
3.
(Not to be made)
Glycerin
Menthol
Alcohol
Witchazel Extract
Water
Preservative
Perfume (water soluble)
5%
0.05%
40%
18.5%
35%
0.05%
1.4%
PRE-SHAVE LOTIONS (not to be made)
For electric razors, the shaving conditions are totally different. The beard
must be dry, the hairs stiffened and raised so that each individual hair can
be caught in the razor combs and clearly removed by the cutting edge.
74
Pre-shave lotions must “set up” the beard, make a coating on the skin on
which the razor glides and act as a lubricant for the cutting head of the
shaver itself.
A basic formula to which small amounts of astringents, menthol, etc. can
be added is:
Isopropyl Myristate
10%
Alcohol
90%
The high proportion of alcohol in this type of preparation is less
objectionable than it would be in an ordinary after-shave lotion.
DEPILATORIES
The term “depilatory” refers to preparations intended for the chemical
breakdown of superfluous hair without injury to the skin.
The desirable requirements of a depilatory may be defined as follows:
1. Non-toxic and non-irritant to the skin.
2. Reacts preferentially with the hair and will be sufficiently rapid to
cause disintegration to the hair before causing any damage of the
underlying and surrounding skin.
3. Preferably odourless
4. Harmless to clothing
5. Cosmetically elegant.
Depilatories usually contain as one of their active ingredients, an alkaline
reducing agent which will cause the hair fibers to swell and produce a
preliminary step to the complete degradation of the hair.
Sulphides and stannites have been used for a long time. The majority of
depilatories available today are substituted mercantans, for example,
calcium thioglycollate in conjunction with calcium hydroxide. Depilatories
based on the enzyme keratinase have also been developed which do not
have the unpleasant odour of sulphide or even thioglycollate depilatories
and are non irritant.
75
Thioglycollate depilatories are non-toxic and possess less odour than the
sulphide type but take longer to act. At the concentration in 5 – 15
minutes depending on the pH of the preparation. This should be about pH
12.5.
A convenient formula of the calcium thioglycollate type is as follows:
Calcium Thioglycollate
Calcium Hydroxide
Calcium Carbonate, Precipitated
Cetyl Alcohol
Sodium Lauryl Sulphate
Sodium Silicate
Water Perfume to
Send 25g.
7.0%
7.0%
20.0%
5.0%
1.0%
2.5%
100.0%
Procedure:
The sodium lauryl sulphate, sodium silicate and cetyl alcohol are made into
a paste with the rest of the water. The two phases are then mixed and
passed through a triple roll mill to remove lumps and gritty particles.
NB.
1. The pH is maintained by a slight excess of calcium hydroxide, which
acts as a reserving of alkalinity.
2. Chalk or other fillers may be added together with thickening agent to
produce thioglycollate depilatories in a paste form.
3. Substances tending to accelerate the depilatory action may be added.
(F)
W/O Cream Bases
Ex. 20: Send 25g of Oily Cream P.C. Label appropriately.
Ex. 21: Cold Cream Base.
℞
Liquid Paraffin
Beeswax
Borax
51.0
15.0
15.0
76
Water
36.0
Send 25g. To be used as directed.
METHOD:
Oily and oil-miscible or oil-soluble ingredients are mixed and melted
together over a heated water bath. The water and water-miscible or
soluble ingredients are also heated together to form a solution. The two
phases are mixed together at the same temperature and stirred (over a cold
water bath, if necessary) until cold.
(G) Pastes
Ex. 22: Send 25g of Zinc and Salicylic Acid Paste B.P. Label as such.
Ex, 23:
℞
Coal Tar
2.0
Zinc Oxide
5.0
Polysorbate 80
0.5
Yellow Soft Paraffin
60.0
Send 25g.
Label: Apply to the affected part twice daily.
METHOD:
Mix the coal tar with polysorbate 80. Levigate the zinc oxide with a small
proportion of the soft paraffin and incorporate the coal tar/polysorbate 80
mixture in the remaining soft paraffin. Triturate the two portions
together.
NOTE: The polysorbate 80 serves a dual purpose. It functions as a
dispersing agent and also in the removal of the ointment from the skin.
77
(H) OTHER COSMETIC PRODUCTS
(1) DEODORANTS AND ANTIPERSPIRANTS
The perspiration mal-odour is due to apocrine sweat, which contains an
appreciable amount of potentially odour-producing lipid and
proteinaceous matter. When the latter reaches the skin surface it becomes
subject to bacterial attack resulting in its decomposition. The
decomposition product formed usually gives rise to the distinctive axillary
or body mal-odour. These products include low molecular weight fatty
acids mercaptans, ammonia, aromatic amines, indoles and hydrogen
sulphide. It has been shown that perspiration odours do not develop in
sterile mixtures of insoluble sediments of perspiration.
For the control of body odour, two approaches have been suggested.
1. The topical application of suitable antiseptics to prevent bacterial
decomposition, i.e., the use of deodorants.
2. The topical application of suitable astringent substances to reduce the
flow of perspiration i.e. the use of antiperspirants. The modern trend
is to formulate preparations combining deodorant as well as
antiperspirant properties.
The most widely accepted antibacterial compound for use in deodorants
are hexachlorophene (gas), bithionol, quaternary ammonium compounds,
neomycin, ion-exchange resins and metal chelates of 1,3 diketones.
Commercially available antiperspirants are largely based on astringent
aluminium compounds such as aluminium chlorhydrate, aluminium
sulphate and aluminium chloride. Various theories were put forward in
respect of the mode of action of antiperspirants and the conclusion reached
was that aluminium compounds reduce sweating by obstructing sweet
glands rather than by exerting a direct effect upon them.
Moreover, aluminium compounds possess deodorant effect due to
inhibition of bacterial activity by virtue of the relatively low pH of their
preparations and by neutralization of the mal-odour by the chemical
combination with the odoriferous substance.
78
A simple basic formula for a liquid deodorant antiperspirant is as follows:
Aluminium Chlorhydrate
20.0%
Propylene Gglycol
5.0%
Alcohol
10.0%
Germicide
0.2%
Perfume
9.5%
Water to
100.0
Send 25ml.
Cream Antiperspirant:
Aluminium Chlorhydrate
Glyceryl Monostearate (soap free)
Spermaceti
Perfume
Glycerin
Water to
Send 25g.
20.0%
20.0%
5.0%
9.5%
3.0%
100.0%
(2) SKIN CLEANERS
The use of soap and water in reasonable amounts will clean satisfactorily
most normal skins and also those in chronic phase of many diseases. There
is, however, a well-established place in cosmetic practice for nonsaponaceous detergents. Women whose facial skin are excessively dry or
are irritated by soap and water are advised to use a cleansing cream or
lotion.
A satisfactory cleansing cream should be mild on the skin, with a near
neutral pH and should readily wet to the touch not too greasy and not
excessive in quantity.
Suitable cleansing creams could be based on the following formula: -
79
1. O/W Emulsion Type:
℞
Beeswax
8.0
Mineral Oil
49.6
Hard Paraffin
5.0
Soft Alcohol
8.4
Cetyl Alcohol
3.0
Sodium Lauryl Sulphate 3.0
Water to
100.0
Send 25g.
METHOD OF PREPARATION:
Melt the solid substances in an evaporating dish over a water bath (i.e.
cetyl alcohol, beeswax and hard paraffin). Then add the mineral oil and
soft paraffin. Dissolve the sodium lauryl sulphate in the warm purified
water which had been freshly boiled and cooled to about 50oC and mix this
solution with the melted ointments. Stir constantly until cold using a
pestle, and not a glass rod.
2. W/O Emulsion Type (Not to be made)
(a) ℞ Beeswax
Mineral Oil
Span 80
Anhydrous Lanoline
Water to
Send 25g.
100
25g
10
3.1g.
100g.
Beeswax Borax Type
(b) ℞ Beeswax
14%
Almond Oil
50%
Borax
1%
Water
31%
Send 25g.
80
NOTE: Spermaceti is usually added as a thickener. A preservative and
perfume are also included.
METHOD OF PREPARATION:
Dissolve the beeswax to the almond oil at 60oC. Add the borax dissolved
in the water at the same temperature. Mix and stir constantly until cold.
The above beeswax-borax cream is still one of the most popular types of
cleansing cream and is the familiar COLD CREAM. It is emulsified insitu
by beeswax and borax.
3. Cleansing Lotion
Triethanolamine3g.
Stearic acid
Beeswax
Liquid paraffin
Water
Send 25g.
5g.
2g.
35g.
55g.
METHOD:
Dissolve the triethanolamine in water and heat to 60oC. Melt the stearic
acid, beeswax and liquid paraffin together and add the aqueous solution to
the oil at the same temperature with continuous trituration.
(3) SHAMPOOS AND HAIR CREAM
Shampoos
These are products possessing cleansing and foaming properties, and are
characterized by leaving the hair soft, lustrous and manageable. Shampoos
may be classified according to their physical appearance into
1. Liquid shampoos
2. Cream shampoos
3. Powder shampoos.
81
By careful formulation, excellent shampoos could be obtained either from
soaps or synthetic detergents.
1. Liquid Shampoos
℞
Coconut Oil
Olive Oil
Sodium Hydroxide/Potassium Hydroxide
Alcohol
Water to
Send 25ml.
21g.
3g.
1:2
15ml.
100ml.
Procedure:
The weighed amounts of sodium hydroxide and potassium hydroxide are
dissolved in the least amount of water (about 2ml) and solution is heated.
The solution of alkali is added to the melted oils mixture on a water bath
until complete saponification. The soap is dissolved in hot water. After
cooling, alcohol is added and the volume is finally adjusted with water.
2. Cream Shampoos
℞
Sodium Lauryl Sulphate
Sodium Stearate
Lanolin
Water
Send 25g.
50g.
8g.
1g.
100ml.
Procedure:
Stearic acid is melted on a water bath, sodium hydroxide is dissolved in a
small volume of water the solution is heated and added to the molten
stearic acid. After complete saponification, lanolin is added. A paste of
sodium lauryl sulphate in the remaining amount of water is prepared and
mixed with the soap formed.
82
Hair Cream
The ideal aid to hair grooming would probably be non-oily, non-gummy,
non-resinous and likely to form an invisible stable, resilient, adequately
controlling yet readily removable film on the hair. Successful brilliantine
cream of the water-in-oil type are usually based on relatively simple
formulae. In spite of this, they are not easy to imitate. Strict attention to
the reliability and uniformity of raw materials is as essential as effective
control of all processes and temperatures. Comparative analysis of several
different commercial products gives an oil content of 35 – 50% an aqueous
phase of 50 – 60% and an emulsifying agent of under 4%.
℞
Light Liquid Paraffin
White Soft Paraffin
White Beeswax
Oleic Acid
Lime Water
Perfume
Make 25g.
40%
6%
3%
0.5%
50%
0.5%
Procedure:
Slowly add the lime water (freshly prepared) to the light liquid paraffin,
beeswax and oleic acid held at 70oC. Continue to stir until cold. Add the
perfume at about 45oC.
NOTE: Creams of the above type have the advantage of reasonably good
stability on storage provided that they are passed through an homogeniser
and carefully processed in other aspects. They break down readily when
mechanically disturbed by rubbing on the hair and they act more like
brilliantine oil then a cold cream.
83
400 LEVEL
84
POWDER TECHNOLOGY & DOSAGE FORM
DESIGN
POWDERS
Oral powders are mixtures of powder substances intended for
administration by mouth. They are usually mixed with water before
administration. But some oral powders for veterinary use are administered
by mixing with animal ration. Furthermore, most raw materials required
in the preparation of tablets and capsules are available as powders, which
are compressed into the tablet dosage form after granulation process.
Classification:
They can be classified according to their size: (i.e. ability to pass through a
mesh aperture):
1. Coarse Powder
2. Moderately Coarse Powder
3. Moderately Fine Powder
4. Fine Powder
5. Very Fine Powder
6. Ultra-Fine Powder
PREPARATION OF INSUFFLATION
AND DUSTING POWDERS
INSUFFLATIONS
Synonym: Insufflations.
These are powders, which are intended to be blown by means of an
insufflator onto or into the affected part, e.g. Ear, Nose and Throat.
The preparation of insufflations is similar to the preparation of dusting
powders.
85
Frequently, insufflations contain substances, which liquefy when mixed.
Most often encountered are camphor, menthol, phenol, ephedrine and
thymol.
To avoid the production of a down mass, disperse each of the liquefying
substances in part of the base, sieve, and then mix the parts lightly
together, with a spatula, on a place of paper, patients should be warned to
store in a dry place.
Packing: Glass jar with screw cap.
Labeling: “Not to be taken”.
PRACTICAL
℞
Menthol
Camphor
Send 20g.
Make the insufflation.
Label: To be used as directed.
5
5
METHOD
1. Powder the menthol in a glass mortar and add approximately half the
Heavy Magnesium Carbonate, using the “doubling up” techniques,
and pass through a No.60 sieve.
2. Separately powder the camphor in a glass mortar and add the
remaining heavy magnesium carbonate and sift.
3. Mix the two portions from (1) and (2) lightly together on a piece of
paper, using a spatula.
4. Pack and label.
DUSTING POWDERS
Synonyms: Pulvis Consperous.
These are usually admixtures of two or more substances in fine powder,
and are intended for application to the skin. Mineral ingredients such as
Talc and Light kaolin are often used, and since they may be contaminated
86
with pathogenic organism, should be heat-treated before use (B.P.
maintain at 160oC for 1 hour). The ingredients are mixed in ascending
order of weight and are passed through a No.60 sieve before packing.
Containers: Cylindrical paper – board boxes with sprinkler holes on
closure. For economy, powder jars are used.
Labeling: “For external use only” and “store in a dry place”. “Not to be
applied to open wounds or areas of broken skin”.
PRACTICAL
℞
Zinc Oxide
20.0
Salicylic Acid
2.0
Starch Powder
78.0
Send 30g.
Label: The dusting powder. To be applied as directed.
METHOD:
1. Weigh out the salicylic acid and powder finely in a glass mortar.
2. Weigh out the zinc oxide and place in the glass mortar a quantity
roughly equal to the bulk of salicylic acid therein. Mix thoroughly,
then add a further quantity of zinc oxide, equal in bulk to the contents
of the mortar, and continue in this manner until all the zinc oxide has
been added. Note below:- This process is known as “doubling up” and
is used to ensure even dispersion of small quantities in a large bulk of
material.
3. Weigh out the starch and mix with the powder in the mortar.
4. Pass the dusting powder through a No. 60 sieve onto a large piece of
paper.
5. Mix the powder together lightly on the paper, using a spatula since
some separation may have occurred on sieving.
6. Pack in a suitable container and label.
87
PREPARATION OF BULK AND INDIVIDUALLY
WRAPPED ORAL POWDERS
Synonym: Pulverse; Pulv; Pdr:
Powders are usually mixtures of two of more medicaments intended for
internal use. Each does may be wrapped individually or the powder may
be supplied in bulk with, for example, a teaspoonful does.
The general B.P. monographs on powders should be read.
General Principles of Dispensing Powder.
All medicaments plus any added “bulking” agent is reduced to a fine
powder in a glass mortar before mixing.
Mixing is carried out using the “doubling-up” process in order to ensure
uniformity of the final product, and even dosage when the powder is
divided into proportions.
Bulk powders are prepared according to the general rules and packed in
wide mouthed screw-capped jars.
Single-dose, individually wrapped powders are prepared in bulk and each
dose is then weighed separately and placed on a powder paper. This paper
is then folded to enclose the powder and prevent any leakage on
subsequent handling. All the powders of a particular batch must be
uniformly wrapped and the individual powders held together with an
elastic hand or dispensing thread before packing them into a powder box.
Note: When a small quantity of a potent medicament is ordered by itself as
a powder, it should be diluted by trituration with an amount of an inert
diluent such as lactose so that the weight of the triturate to be taken as a
dose is 120mg. The triturate should then be suitably wrapped as single
doses.
88
PRACTICAL
1. Bulk Oral Powder:
℞
Compound Magnesium Carbonate Powder (BP 1988).
Synonym: Pulbis Magnesii, carbonates compositus; Pulv. Mag.
Carb. Co.
Calcium Carbonate
Heavy Magnesium Carbonate
Sodium Bicarbonate
Light Kaolin
Send 30g.
Label: Two teaspoonfuls to be
after meals.
400g
400g
300g
100g.
taken in water, three times a day
METHOD:
1. Weigh out the ingredients
2. Mix in a mortar in order of ascending weight
3. Pass through a No. 60 sieve
4. Mix lightly with a spatula and pack in a screw-caped jar.
2. Single Dose Powders:
℞
Hyoscine Hydrobromide 0.6mg.
Make the powder
Label: One dose to be taken after food.
METHOD:
1. Weigh out 100mg of hyoscine hydrobromide and triturate with
2.4g of lactose in a glass mortar.
2. Weigh 120mg of this triturate and mix with 0.84g of lactose in a
glass mortar.
89
3. Prepare five powder papers and pack 120mg. of the powder in
each.
4. Check the weight of powder left.
5. Label and pack the product.
3. ℞ Sod. Bicarb.
700mg
Phein Pulv.
100mg
Peppermint Oil
0.03ml.
Make the powder.
Label: One dose to be taken with water after food.
Notice that the exact weight of each powder is unknown. It will be about
800mg. It is necessary therefore, to make the total weight the bulk
powder up to a suitable figure by adding a suitable inert substance.
METHOD:
1. Weigh and mix the solid ingredients (for 10 powders)
2. Add the peppermint oil and mix thoroughly.
3. Transfer the whole of the powder to a balance pan and add sufficient
lactose to give a total weight of 10g. (Each powder will then weigh
10).
4. Mix the lactose into the other ingredients. Weigh out the individual
powders into double powder papers, the inner paper being cut from a
waxed or greaseproof paper is smaller than the outer paper all the
way round. Wrap each powder as it is weighed to avoid excessive
lose of peppermint oil.
90
DENTIFRICES
These are preparations intended for use with a tooth brush for the process
of cleansing the surface of the tooth. They could be classified according to
their physical appearance, into:
1.
2.
3.
4.
Powder Dentifrices
Paste Dentifrices
Gel Dentifrices
Liquid Dentifrices
Functions of Dentifrices
The normal oral cavity supports a very large and varied population of
bacteria, fungi and protozoa. In spite of what advertisers claim or imply,
dentifrices are intended primarily to aid in cleansing the tooth and are of
value just for that purpose. Some pastes, of course, go beyond the
requirements of simple detergency and brushing the teeth with a dentifrice
to include the aesthetic objective of removing food particles from around
the teeth, polishing the teeth and freshen up the mouth by importing a
cool and pleasant flavour.
Therefore, the functions of dentifrices are:
a. Polishing of the tooth;
b. Reduction of the incidence of tooth decay;
c. The maintenance of a healthy gum;
d. Reduction of mouth odour.
Ingredients of tooth preparations include:
(a) Abrasives
(b) Surface active agents or detergents
(c) Flavouring agents and
(d) Sweetening agents.
Tooth pastes contain, in addition to the above ingredients, water,
humectants, binders and preservatives. They may also contain:
91
1. Fluorides to strengthen the teeth and to decrease their
susceptibility to decay.
2. Anti-enzymes to prevent putrefaction resulting from enzymatic
decomposition of sugars. They should be non-toxic and free from
unpleasant taste.
3. Colouring matter e.g. chlorophyll.
1. ABRASIVES
An abrasive is an ingredient with rough surfaces i.e. a mechanical cleansing
agent whose functions are:
(a) Removal of debris and residual stains from the teeth.
(b) Polishing of the tooth surface.
Examples of common abrasives are: Calcium Carbonate and Calcium
Phosphate.
2. SURFACE ACTIVE AGENTS
Soaps are rarely used due to their irritant effect and their incompatibility
with certain ingredients of dentifrices. Synthetic detergents, such as
sodium lauryl sulphate are more commonly employed in modern
dentifrices.
3. BINDERS
Simple mixing of the solid and liquid phases of tooth paste is inadequate to
prevent the separation of the liquid phase particularly during storage: a
binder must be added.
Examples are:
Glycerin of Starch
Gum Arabic
Gum Tragacanth and
Methyl Cellulose.
92
ANALYSIS OF POWDER PARTICLES
The particle size of drugs have significant effect on the physical, chemical
and biological properties of solid dosage forms such as degree of mixing,
chemical stability, rate of dissolution and drug blood level. It is therefore
an important particulate property of characterizing a material and
understanding its behavior.
The size of a particle is the dimension which best states the size
subdivision. For a sphere this is unambiguously the diameter, for cuboids,
it is the length of one edge. Derived diameters are determined by
measuring a size dependent property of the particle and relating it to a
linear dimension. For irregular particles, the assigned size usually depends
on the method of measurement. Therefore the technique of particle size
analysis should reflect the process under control, e.g. for tableting,
particle volume is important; for catalysts, surface area is important and
measurements are referred to an equivalent spherical diameter.
A. Particle Size Analysis Methods:
Microscopy:
1. Collect a sample of the powder with a spatula and spread lightly on a
slide and view under a light microscope.(a) Describe the shape.
2. Insert an eyepiece graticle and calibrate it using a stage micrometer.
Determine the size of particles and count the number of the different
particles under view at various locations on the slide. Create a table of
distribution of the particles using the Normal Distribution Method
namely, Size Range, Mean Size Range, Number of Particles in each size
range, etc. (b) Plot the Size-Frequency distribution both as a Histogram
and a Curve. (c) Calculate: Arithmetic Mean Diameter, (∑nd/∑n), and
Mean Surface Diameter √(∑nd2/∑n).
Sieve Method:
1. Weigh 100 g of a given powder (vegetable drug or pure chemical such
as ASA). Arrange the sieves in order of decreasing sieve number or
aperture size in a sieve shaker. Operate the sieve shaker until no further
change in the weight of the primary sample is observed. (a) Determine the
93
weight of the samples collected from the different sieves. (b) Name the
class(es) of powder you have produced. (c) Plot the distribution obtained
as Cumulative % Weight Frequency Undersize.
B. Mixing of Powders
Content uniformity is largely dependent upon the quality of the initial
powder mixture and particle size distribution.
Factors affecting mixing include particle size distribution, density, shape
and attraction, mixing time and types of mixer.
Further discussions on the different types of mixers, forces that are
relevant for mixing to occur and mechanism of mixing are found in your
lecture notes or relevant textbooks of pharmaceutical technology.
Degree of Mixing:
This is the qualitative expression, which defines the state of a mix. Such
expression also allows the course of mixing to be followed and the
performance of different mixers to be compared.
PRACTICAL
Incorporate a dye (Methylene Blue), 10 mg, into a given 1 kg base. Collect
samples from different parts of the mix at 5 minutes intervals and assay for
the dye
Method of Assay: Dissolve the sample in a specific volume of water and
read the absorbance using UV/Visible Spectrophotometer.
NB: The smallest amount of sample collected for analysis is call the scale
of scrutiny (the dose unit for such medicament is recommended)
The Mixing Index is calculated by:
M=
ࡿD
ࡿ
Where; M = Index of Mixing
SD = Standard Deviation
S = SD of samples drawn from the mixture under examination
M approaches unity as mixing is completed.
94
C. Flow Properties of Powder:
Based on their flow properties, powders can further be classified as:
1. Free flowing powders
2. Cohesive powders
Free flowing powders are usually of coarse dimension while the cohesive
types are of fine particle size.
(a) Bulk Density: Bulk density is defined as the weight per unit volume
of material. The bulk density of a powder is the ratio of the mass of an
untapped powder sample and its volume including the contribution of
the interparticulate void volume. Hence, the bulk density depends on
both the density of powder particles and the spatial arrangement of
particles in the powder bed. The bulk density is expressed in grams
per mL (g/mL)
(b) Tapped Density: If the granules in the measuring cylinder are
tapped, a volume less than the bulk volume is obtained. This is the
tapped volume. The ratio of the weight of the granules over its
tapped volume is known as the tapped density.
(c) Carr’s Index: An alternative test to characterize the flow of
particulate solids is the determination of the Carr’s index. This
parameter relates the bulk (or “fluff”) density of the material (the
volume occupied by a certain mass of powder when gently poured
into a measure) to the tapped density (the volume occupied by that
same mass of powder after a standard tapping of the measure to
consolidate the powder). This can be mathematically expressed as:
Carr’s index = 100(V0 - VF)/V0
V0 = unsettled apparent volume
VF = final tapped volume
Values below 15% would indicate excellent flow. Powders with values
over 20% would have poor flow.
95
(d) Hausner Ratio: The Hausner ratio is similar to the Carr’s index. It
is computed simply by dividing the tapped density by the bulk
density.
=V0/VF
(e) Angle of Repose:
This is the maximum angle possible between the surface of a pile of a
powder and the horizontal at which the powdered particles starts to
slide down. (This assay is useful for free flowing powders).
PRACTICAL
Methods:
1. Funnel Method: Allow the powder to pour out from a funnel. (a)
Measure the angle it forms with the base.
The Funnel and Rotating Drum Methods are characterized by high
human error and therefore results are not reproducible.
2. Hollow Tube: Fill a hollow tube sitting on a base with the same
diameter as the tube with the powder. Remove the tube to allow
excess powder to fall off. (b) Measure the angle of the slope of the
heap with the base using a semicircle rule.
3. Drained Cylinder: Fill a wide cylinder with the powder and then
remove the plug at the base in order to drain off the powder. (c)
Measure the angle of the drained cone formed within the cylinder.
(f) Flow Through an Orifice:
This is used to determine whether a powder is free flowing or not. It
is usually expressed as weight collected per unit time. i.e. U(g.s1) =
W(gm)/t(sec)
96
PRACTICAL
Methods:
Drained Cylinder Method:
Fill the cylinder with the powder, remove the plug at the base of the
cylinder and collect the powder flowing out through the orifice into a
beaker. (a) Determine the time it takes the powder to completely flow
out. (b) Determine the weight of powder that flowed out. (c) Plot the
effects of the following factors, particle/granule size and orifice size, on
the flow rate of the powders used.
(g) Tensile Strength Measurement:
Tensile strength is a measure of the force/unit area required to split
the powder bed under tension. This measurement applies only to
cohesive powders.
PRACTICAL
Methods:
Tideswell & Todyfield Method (Split Plate Method)
Assemble the apparatus, clamp the cells, pack the powder to be
determined into it and adjust the plunger to the required stress (pressure)
until a depth of 1cm is covered. Tilt the cell at a rate of 100/min until the
bed fractures. (a) Measure the angle, , of the plane to the horizontal at
which the bed fractures. Calculate the cohesion using the formula:
Cohesion =
ࢃࢍࡿ࢏࢔ࣂ
࡭
dynes/cm2
Where: W = Total Weight (i.e. sliding half of cell, its content
and the rollers)
g = Acceleration due to gravity
A = Surface Area
 = Angle of the plane to the horizontal
97
Other Methods Includes;
Warren Spring tensile testing, a motorized method employed in
fracturing the packed bed on a horizontal plane. The tensile
strength is calculated as:
T=
૛ࡼ
ࡰ࢚࣊
Where P = Applied Force
D = Diameter of the compact
T = Thickness of the compact
π = Constant (3.143).
98
DOSAGE FORM DESIGN
A. TABLETS
The lecturer takes the students through the tablets manufacturing
laboratory and introduce them to the different aspects of tablets
manufacture and machines.
The technologist describes how the machines are operated and maintained
GRANULATION, DRYING PROCESSES & TABLET
COMPRESSION
Granulation Techniques:
A. Wet Granulation
Wet granulation is a process of using a liquid binder to lightly
agglomerate the powder mixture. The amount of liquid has to be
properly controlled, as over-wetting will cause the granules to be too
hard and under-wetting will cause them to be too soft and friable.
Aqueous solutions have the advantage of being safer to deal with than
solvent-based systems but may not be suitable for drugs which are
degraded by hydrolysis.
Procedure
1. The active ingredient and excipients are weighed and mixed.
2. The wet granulate is prepared by adding the liquid binder–adhesive to
the powder blend and mixing thoroughly. Examples of
binders/adhesives include aqueous preparations of cornstarch, natural
gums such as acacia, cellulose derivatives such as methyl cellulose,
gelatin, and povidone.
3. Screening the damp mass through a mesh to form pellets or granules.
4. Drying the granulation. A conventional tray-dryer or fluid-bed dryer
are most commonly used.
5. After the granules are dried, they are passed through a screen of
smaller size than the one used for the wet mass to create granules of
uniform size.
99
B. Dry Granulation (Slugging)
Dry granulation processes create granules by light compaction of the
powder blend under low pressures. The compacts so-formed are
broken up gently to produce granules (agglomerates). This process is
often used when the product to be granulated is sensitive to moisture
and heat. Dry granulation can be conducted on a tablet press using
slugging tooling or on a roll press called a roller compactor. Dry
granulation equipment offers a wide range of pressures to attain
proper densification and granule formation. Dry granulation is
simpler than wet granulation, therefore the cost is reduced.
However, dry granulation often produces a higher percentage of fine
granules, which can compromise the quality or create yield problems
for the tablet. Dry granulation requires drugs or excipients with
cohesive properties, and a 'dry binder' may need to be added to the
formulation to facilitate the formation of granules.
C. Melt Granulation
Melt granulation is a process by which pharmaceutical powders are
efficiently agglomerated by the use of a binder which melts during the
process. Examples of binders traditionally used includes; Poloxamers,
Polyethylene Glycols, Carnauba Wax, Beeswax, Paraffin Wax,
Stearic Acid and Hydrogenated Castor Oil
PRACTICAL
℞ 20 Tablets of Paracetamol 500mg
Paracetamol
500mg
Lactose
50mg
15% Maize Starch Mucilage
q.s
Maize Starch Powder
25mg
Talc
5mg
Magnesium Stearate
5mg
100
Procedure
1. Weight the required amount of Paracetamol powder into a mortar,
mix with sufficient quantity of 15% starch mucilage; make a mould
using your hand and press between your thumb and fore-finger. How
does it feel? Record your observation.
2. Press through a large pore sieve to produce beads of extruded wet
granular sized particles.
3. Dry in an oven at about 50-60oC for about 30 min, mill the dry mass
to granular size. What other process of granulation and drying do you
know?
4. Determine the flow properties of the granules by calculating the a.
Bulk Density, b. Tapped Density, c. Carr’s Index, d. Hausner Ratio
and e. Angle of Repose.
5. Carry out the compression of these granules and the powders from
which they were formed using the manually operated single punch
machine.
IN-PROCESS CONTROLS IN TABLETING
In-process controls (IPC) are checks that are carried out before the
manufacturing process is completed. The function of in-process controls is
monitoring and – if necessary – adaptation of the manufacturing process in
order to comply with the specifications. This may include control of
equipment and environment.
In-process controls may be performed in regular intervals during a process
step (e.g. tabletting) or at the end of a process step (e.g. granulation,
blending). The objectives of in-process control are both quality control
and process control.
• Tablet weight variation,
• Disintegration time,
• Content uniformity and homogeneity,
• Dissolution time and rate,
101
PRACTICAL
From the previous practical, determine the following;
(a) Weight of tablets produced
(b) Tablet dimensions (diameter & thickness)
(c) Friability
(d) Crushing Strength (hardness/tensile strength) using the formula
T=
૛‫۾‬
۲ૈ‫ܜ‬
(e) Disintegration time
(f) Content of active drug and
(g) Dissolution according to the official books
102
B. CAPSULES
DEFINITION OF CAPSULES
Capsules are solid dosage forms in which the drug substance is enclosed in
either a hard or soft soluble container or shell of a suitable form of gelatin.
The word capsule is derived from the Latin word ‘capsula’, meaning a
small box. In current English usage, it is applied to many different objects
ranging from flowers to spacecraft.
TYPES OF CAPSULES
There are two types of capsules,
1. Hard gelatin capsules
2. Soft gelatin capsules
The hard gelatin capsule which could be said to be two-piece consist of
two hard pieces in the form of cylinders closed at one end, the shorter
piece which is called the ‘cap’ fits the open end of the longer piece which
is called the ‘body’. The soft capsule on the other hand is said to be the
one-piece and is a soft globular gelatin shell.
Although the standard capsules have the conventional oblong shape,
exceptions are capsule products by Lilly and Smith Kline & French
(SK&F), which are of a distinctive shape. For Lilly products, capsules are
used in which the end of the base is tapered to give the capsule a bullet-like
shape; products encapsulated in this form are called ‘pulvules’. The SK&F
Spansule capsule differ in that both the ends of the cap and the body are
angular rather than round.
Examples of materials that are preferably formulated into capsule dosage
forms of hard gelatin types include dried powdered plant parts and some
antibiotics
Students should obtain more information from the official books and
product brochures on the formulation, packaging and storage of capsules
103
CAPSULE CAPACITIES
Size
Volume (ml)
000
00
0
1
2
3
4
5
1.37
0.95
0.68
0.50
0.37
0.30
0.21
0.13
Fill weight at
powder density of 0.8g/cm3(g)
1.096
0.760
0.544
0.400
0.296
0.240
0.168
0.104
SOME REASONS FOR FORMULATION OF CAPSULES AS
DOSAGE FORM
1. Some drugs have poor binding and compressibility property and hence
are better formulated as capsules
2. Capsules are used to mask bitter and unpleasant taste of drugs
3. To improve bioavailability. This is because of the fast dissolution of the
shell and absence of compaction.
4. Hard gelatin capsules allow for a degree of flexibility of formulation that
is not obtainable with tablets. It is often easier to formulate hard gelatin
capsules than tablets because there is no requirement that the powders
must be formed into a coherent compact.
5. Hard gelatin capsules allow for flexibility in clinical testing and are
widely used in preliminary studies of drugs.
PRACTICAL
Send 8 hard capsules of 150mg capacity, each containing 550 micrograms
of Hyoscine hydrobromide.
A suitable filler should be selected
104
PRACTICAL
Send 15 capsules each containing 250 mg Ampicillin trihydrate equivalent
to 150 mg Ampicillin base.
1. Use a suitable filler, lubricant and glidant.
2. Make a capsule weight of 400 mg.
3. Label to be used as prescribed
PRACTICAL
Send 500 mg capsule of the formula
Occimum gratissimum
100 mg
Venonia amigdalina
150 mg
Andrographis paniculata 100 mg
Garcenia kola
100 mg
Lubricant (Talc)
qs
Disintegrant
qs
Label: To be swallowed twice daily after food
Analysis
Analysis of capsules is similar to that of tablets with the exception of
hardness and friability tests
105
C. MICROENCAPSULATION
DEFINITION OF MICROENCAPSULES
These are systems consisting of fine solid particles, solutions, or emulsion
droplets coated reproducibly with extremely thin polymeric films or
shells. The coated particles or droplets are generally referred to as
microcapsules.
The term “microcapsule” has been defined as a spherical particle with a size
varying between 1m and 1000m containing drug in the core
Microsphere is a term often used synonymously with microcapsule. In
strict sense Microcapsules are spherical particles made up of a continuous
phase of one or more miscible polymers in which particulate drug is
dispersed, at either the macroscopic (particulate) or molecular (dissolved)
levels. Microsphere is different from microcapsule by having no welldefined wall or envelope.
Different methods of encapsulation result in most cases, in either a
microcapsule or a microsphere. In addition, some related terms are used
as well. For example “microbeads” and “beads” are used alternately.
“Spheres and “spherical” particles are also employed for large size and rigid
morphology.
Liposomes, otherwise known as multilamellar vesicles (MLV), consist of
one or more phospholipid bilayers alternating with aqueous drug
compartments (Okhamafe, 1990).
Nanoparticles differ from conventional microcapsules only in being
much smaller. They are of colloidal dimensions with particle diameter in
the range 10-1000 nm. Microencapsulation has found application in a
number of fields: pharmaceutical, biomedical, agricultural and cosmetics,
to mention but a few.
106
Reasons for Formulating Drugs as Microcapsules
Microencapsulation technology was first applied in engineering industrial
production. This technology is now being applied in almost every aspect of
science including pharmacy, biotechnology, agriculture, cosmetics and
also many scientific disciplines: chemistry, biology and physics.
1. To improve formulation of incompatible drug components.
2. In Pharmacy, other reasons include achieving ccontrol of drug release,
masking of unpleasant taste, Protection of labile drugs, minimize gastric
irritations, separation of incompatible drugs, change liquid drugs to solid,
entrapment of carcinogens, drug targeting, bioartificial organs and
production of biopharmaceuticals.
Materials for Producing Microcapsules
Some of the materials that are currently being used or studied for
controlled drug delivery include
 Poly-2-hydroxy ethyl methacrylate
 Poly-n-vinyl pyrrolidone
 Polymethyl methacrylate
 Polyvinyl alcohol
 Polyacrylic acid
 Polyacrylamide.
 Polyethylene-co-vinyl acetate
 Polyethylene glycol
 Polymethacrylic acid
In recent years additional polymers designed primarily for medicinal
applications have entered the arena of controlled release. Many of these
materials are designed to degrade within the body. Among them are:
o Polylactides
o Polyglycolides
o Polylactide-co-glycolides
o Polyanhydrides
o Polyorthoesters
107
The greatest advantage of these degradable polymers is that they are
broken down into biologically acceptable molecules that are metabolized
and removed from the body via normal metabolic pathways.
Biodegradable materials produce degradation by-products that must be
tolerated with little or no adverse reactions within the biological
environment
Methods of Producing Microcapsules
A wide range of microencapsulation techniques has been developed. Two
major classes of encapsulation methods have evolved; chemical and
physical.
Chemical methods involve polymerization during the process of
preparing the microcapsules. Examples of methods in this class are
interfacial or in situ polymerisation, simple and complex coacervation,
solvent extraction, phase separation, counterion coacervation,
emulsion/interfacial polymerisation, internal gelation and solvent
evaporation.
Physical methods involve the controlled precipitation of a polymeric
solution wherein physical changes usually occure e.g. spray drying, spray
chilling, rotary disk atomisation, fluidized bed coating, stationary nozzle
coextrusion, centrifugal head coextrusion, submerged nozzle coextrusion
and pan coating.
The classification of the various methods of microencapsulation is not easy
due to the huge and increasing number of processes involved in
encapsulation. Also specific techniques can be hybrid of two or more
methods or can use different mechanism simultaneously. Moreover, many
names have changed throughout the years. Many new patents evolve solely
on the basis of novel ways to produce microspheres. Thus, many scientists
try to develop a systemic nomenclature for encapsulation depending on
the nature of the polymer and the drug to be incorporated. Students
should look up some published literature for other new methods of
microencapsulation.
108
Gelation
This method can be used for alginates due to their ability to form gels by
reacting with calcium salt. It has been used as a method of enclosing viable
cells, tissues and other labile biological substances within a semi permeable
membrane. Other materials that have been successfully encapsulated by
this method include, cloths dyes, proteins, DNA and recently, plant
extracts. The method involves the extrusion of a suspension of the cell or
tissue through a microdroplet-forming device producing microbeads,
which fall into CaCl2 solution and form, gelled microbeads with the cells
or tissues entrapped. These cell-containing, gel microbeads are then
treated with a solution of polylysine, which displaces the surface layer of
calcium ion, and form a permanent polysalt shell or membrane. Finally the
interior calcium alginate gel is “liquefied” either to stay or to come out
(depending on molecular weight and size of the starting alginate) of the
capsule with calcium sequestrate such as buffered citrate solution
PRACTICAL
Formulate insulin microcapsules for oral administration such that 100 mg
of microcapsules will contain 200 IU of insulin
PRACTICAL
Formulate Calcium alginate microbeads for the entrapment of Vit A for
incorporation into table salt as “Vitamin A fortified table salt” such that
200 mg microcapsules will contain an equivalence of 20 mg Vit. A
Preparation of Coating Material (0.1% Chitosan Solution)




Dissolve the calculated amount of chitosan in distilled water,
containing 1% glacial acetic acid with the aid of a magnetic stirrer.
Adjust the viscosity of the chitosan solution by digesting overnight
with 2.14 ml of 1%w/v Sodium Nitrite Solution.
Add the calculated amount of Calcium chloride dehydrate.
Add Polysorbate 80 (2 drops) a non-ionic surfactant to reduce
surface tension of the coating solution.
109


Adjust the pH of the solution to 5.5 using NaOH pellets and
solution.
Filter the solution and adjust its volume to 1000 ml.
Preparation of Core Materials



Dissolve Sodium alginate (1%) in distilled water
Add the active drug and stir using a magnetic stirrer until it
dissolves.
Adjust the volume to 100 ml.
Method of Microencapsulation
The electrostatic droplet generator system can be used for microcapsule
preparation. Spherical droplets are formed with a syringe pump (ColeParmer Instrument Company, Illinois, USA) on which is fitted a different
sizes of 90o blunt tip needle depending on the microcapsule size range
desired.
 In the laboratory, students are to use hypodermic syringes to
which different sizes of needles are mounted
 Load the core material into the syringe and extruded the syringe
content into the coating material in a vertical position.
 Describe your result
 Filter and air-dry the particles.
Analysis of Microcapsules
Carry out the following analysis on the microcapsules you have produced.
1. Characterization of weight, size and shape of microcapsules
2. Morphology
3. Entrapment efficiency
4. Drug release profile
110
DETERMINATION OF VISCOSITY OF NEWTONIAN
FLUIDS.
Introduction and Theory.
The viscosity of a liquid is that property which is responsible for the
internal resistance offered to the relative motion of different parts of the
liquid. This internal resistance is closely connected with the interaction
between separate molecules of the liquid and the structure of the liquid
phase. When a liquid flows through a tube, the “layer” of liquid in contact
with the wall of the tube is stationary, whereas the liquid in the center has
the highest velocity.
Newton assumed the shearing forces (F) between two parallel planes in a
liquid in relative motion to be proportional to the area of the planes and to
the velocity gradient between them; he wrote his law for infinitely near
planes in the form:
dv
F n A
d
Where
dv
= velocity gradient perpendicular to the planes,
d
A = area of the planes
H = coefficient of dynamic viscosity.
The absolute c.g.s. Unit of the coefficient of viscosity is the POISE (g.cm-1
sec-1).
A liquid has a viscosity of 1 poise if a steady tangential force of 1 dyne
produces a relative viscosity of 1cm per second between two parallel
planes of area 1cm2 separated by 1cm and immersed in the fluid.
The new S.I. unit of dynamic viscosity is Newton second per square
meter. The poise is one of the units still allowed in conjunction with S.I.
units and is 10-1s-1.
111
For most pure liquids and many solutions, Newton’s law has been
confirmed for streamline or laminar flow, i.e. it is independent of the
velocity gradient and such liquids are said to exhibit Newtonian viscosity.
At a certain high critical liquid velocity (Vc) orderly steaming fluid motion
is replaced by disorderly turbulent flow involving dissipation of energy in
dry formation and the Newtonian Law is not applicable. Reynolds showed
that the critical velocity could be expressed by: Vc = Rc h
PD
Where Rc is constant (Reynoldn a number) and it is approximately 2000
for long tubes.
D = diameter of tube
P = density of fluid
Capillary Flow Method for Measuring Viscosity.
Under conditions of streamline flow, Poiseuille showed that for narrow
tubes of radius R the volume of liquid V flowing through the tube in time,
t, under a given pressure, p, was related to the resistance to flow as a
function of the area of the tube well the viscosity of the liquid and the
velocity gradient.
V = πR4 Pt
8hl
Where l is the length of the tube, or
H = πR4 Pt
8 Iv
Thus, h = CPt if
πR4 Constant C
8Iv
112
and C = h
Pt
Providing that the viscometer is vertical, the ;pressure P = heg, but for
any given viscometer h and g are both constant, so that p is proportional to
C. Denoting the properties of a standard liquid by subscript 1 and of the
test liquid by subscript 2,
H2 = P2 t2
P1 t1
h1
h2
= h1 = CP2 t2
P1 t1
Where
C
=
h1
P1 t1
And provided P2 is known, measuring t2 enables h2 to be calculated.
The constant C is determined by calibrating the instrument with a liquid of
known viscosity. For the highest accuracy a correction may have to be
made for the pressure used in imparting kinetic energy to the liquid.
The calculation of dynamic viscosity can be tedious since it involves the
determination of density. For this reason the kinematic viscosity is often
used.
Kinematic viscosity = h
e
The unit of kinematic viscosity is the stokes. Kinematic viscosity of a fluid
is thus directly proportional to the time of flow through a capillary tube
(N.B. when liquid flows under its own head of pressure). This is another
unit which may be used in conjunction with S.I. units where kinematic
viscosity is defined as square meter per second. The stoke is thus defined
as 10-4m2s-1.
113
EXPERIMENTAL
Measurement of Viscosity using an Ostwald Viscometer.
Using purified water as the standard liquid and taking the viscosity as 0.01
poise and density as 1 gm cm-1 at room temperature determine the
following:
1. Calculate the constant (C ) of the Ostwald viscometer provided
according to the POISEUILLE’S equation.
2. Determine the dynamic and kinematic viscosities of the 3 unknown
liquids provided.
and
Liquid A has a density of 0.790 gm. cm-1
Liquid B has a density of 0.880 gm. cm-1
Liquid C has a density of 1.324 gm. cm-1
3. Determine the unknown concentration of glycerin provided.
Procedure:
(a) Determine the relative viscosity of different concentrations of
glycerin (suggested concentrations of glycerin/water mixtures to be
prepared are 0%, 10%, 25%, 75%, 90% and 100%).
(b) Plot a graph of hrel against concentration;
(c) Determine the relative viscosity of the unknown samples of glycerin;
(d) From the above graph determine the corresponding concentration of
glycerin.
4. Determine the unknown concentration of ethanol/water mixture
provided.
Procedure:
Follow the same method as in No. 2 above (suggested concentrations of
ethanol/water mixture to be prepared are 0%, 20%, 50%, 60%, 80% and
100%).
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