Introduction - Parenterals
Sterile Products are dosage forms of therapeutic agents that are free of
viable micro organisms. These includes parenterals, ophthalmic products &
irrigating solutions.
 Sterile products are most frequently solutions or suspensions, but may
even be solid pellets for tissue implantation.
 The term “parenteral” means pertaining to outside the intestines. When
referring to parenteral medication, means to deliver medication via a route
other than through digestive tract. The most common route used to deliver
parenteral medication is through injection.
 Parenteral preparations may be given by various routes – Intravenous,
Intraspinal, Intra muscular, subcutaneous & Intradermal, etc.
 All components & processes involved in the preparation of these products
must be selected & designed to eliminate, contamination of all types,
whether physical, chemical or microbiologic origin.
Advantages of Parenterals
 Parenterals are unique among dosage forms of drugs because they are
injected through the skin or mucous membranes into internal body
compartments. Parenterals are useful for patients who cannot takes drug
orally & in emergency situation.
 Drugs may be injected into the specialised area of the body, including
joints (intra articular), joint fluid area (intra synovial), spinal column (intra
spinal), spinal fluid (intra thecal), arteries (intra arterial) and in emergency,
even the heart (intra cardiac).
 Parenterals possess better & faster onset of action & bioavailability than
other dosage forms (solid & liquid orals etc). Biologic products vizpeptide hormones, vaccines, toxoids and antitoxins are best suited for
parenteral route of administration.
 Useful for drugs that are inactivated in the GIT or susceptible first pass
metabolism by liver.
Advantages of Parenterals
 Parenteral products could be administered as sterile solution during an
irrigation procedure as these solutions can enter the blood stream directly
through open blood vessels of wounds or abraded mucous membranes.
 Sterile parenteral products could be administered even as solid
pellets/tablets for tissue implantation and useful for providing sustained
drug delivery (depot injection).
 Parenterals as a dosage form scores better over other conventional
dosage forms (solid/liquid orals) for administration of special categories of
drugs like anticancer agents, immunosupressants, hormones & peptides,
radio opaque & diagnostic agents etc.
 Useful for delivering fluids, electrolytes or nutrients (total parenteral
nutrition) to patients.
Disadvantages of Parenterals
 More expensive & costly to produce as compared to other formulations.
Potential for infection at the site of
extravasation, fluid overload & air embolism.
Risk of needle stick injuries & exposure to blood borne pathogens by
health care workers.
Disposal of needles, syringes & other infusion devices requires special
Improper injection procedures could cause damage to the patient’s nerves,
tissue, veins & other blood vessels.
The presence of traces of physical/chemical contaminants cause irritation
to body tissues & also leads to degradation of product due to chemical
change when thermal sterilisation is employed.
Example: Minute traces of copper increases the rate of oxidation of ascorbic
acid in solution. The contamination arises from water or chemical
components or even the container.
Routes of administration
Intravenous route (IV)
IV injection of drugs provide rapid action compared with other routes of
administration and because drug absorption is not a factor, optimum
blood levels may be achieved with accuracy which is not possible by
other routes.
o In emergencies, IV administration of a drug may be life saving because
of placement of drug directly into the circulation and on the negative
side, once a drug is administered intravenously, it cannot be retrieved.
o Both small and large volumes of drug solutions may be administered
intravenously. IV drugs must be in aqueous solution, they must mix with
the circulating blood & not precipitate from solution.
Routes of administration
Intramuscular route (IM) – IM injections of drugs provide effects that are
less rapid but generally longer lasting than those obtained from IV
administration. Aqueous or oleaginous solutions or suspensions of drug
substances may be administered intramuscularly. IM injections are
performed deep into skeletal muscles.
Subcutaneous route (SC) – This route may be used for injection of small
amounts of medication. Injection of a drug beneath the skin is usually
made in the loose interstitial tissue of the outer upper arm, the anterior
thigh, or the lower abdomen. Prior to injection, the skin at injection site
should be thoroughly cleansed. Irrigating drugs and those in thick
suspension may produce induration, sloughing or abscess & may be
painful. Such preparations are not suitable for SC injections.
Intradermal route – A no.of substances may be effectively injected into the
corium, the more vascular layer of skin just beneath the epidermis. These
substances includes various agents for diagnostic detections,
desensitisation or immunisation. The usual site for intradermal injection is
the anterior forearm.
Water for Injection (WFI)
WFI – It is non-pyrogenic distilled water meant for use in preparations of
medicines for parenteral administration. WFI is obtained by distilling potable
water or purified water from a neutral glass, quartz or suitable metal still fitted
with an effective device for preventing the entrainment of droplets. The 1st
portion of distillate is discarded & the remainder is collected & stored in
conditions designed to prevent the growth of microbes & to avoid any other
Sterile WFI – It is WFI distributed in suitable containers of glass or any other
material, sealed & sterilised by heat under conditions that ensure that water
remains non-pyrogenic. Each container contains a suitable quantity of WFI to
permit the withdrawl of nominal volume.
IP standards & QC tests – 1) Clarity & colour
2) Acidity/alkalinity
3) Oxidisable substances
4) Bacterial Endotoxin Test (BET)
5) Sterility test
6) Residue on evaporation.
Pyrogenecity – Pyrogens are metabolic products of microbes (bacteria,viruses &
mould) and may be present in water. Pyrogens are lipids associated with carrier
molecule usually a polysaccharide or peptide. Pyrogens when injected through ear
vein of rabbits causes marked rise in body temperature (hyperthermia) within 1 hour
of injection. Pyrogens can be eliminated by heating the containers at 210◦C for 3-4
hrs and can be removed from solutions by adsorption on surface of selected
Excipients/Additives used in parenterals
Vehicle – The most frequently employed vehicle for sterile products is water,
as it is the vehicle for all natural body fluids. The tests for checking water
quality includes a) Total solid content b) gravimetric evaluation of organic &
inorganic substances c) Electrolytic measurement of conductivity. The
additional tests for quality of WFI (water for injection) is described in USP
monograph. The another vehicle sterile WFI has been sterilised by a thermal
method, WFI should not have a conductivity of more than 1micro mho.
2) Non aqueous vehicles – It must be selected with great care as it must
be non irritating, non toxic & must not exert an adverse effect on
ingredient of formulation. These must be included because of limited
water solubility of a medicinal substances or it’s susceptibility to
hydrolysis. The screening includes testing of it’s physical properties
such as density, viscosity, pH, miscibility, boiling point, low vapour
pressure & polarity etc.
The United States Pharmacopoeia (USP) specifies restrictions on the
use of fixed oils and they must remain clear when cooled to 10○C to
ensure stability and clarity of injectable product during refrigeration.
Excipients/Additives used in parenterals
The oils must not contain mineral oil or paraffin as these materials are not
absorbed by body tissues. The most commonly used fixed oils in
injections are corn oil, cottonseed oil, peanut oil & sesame oil.
Examples: Water miscible solvents are butylene glycol, Poly Ethylene
Glycol (PEG) 400,600, glycerol, ethanol, propylene glycol. Water
immiscible solvents include fixed oils, ethyl oleate, isopropyl myristate &
benzyl benzoate
3) Solutes – It should be free from pyrogenic & microbial contamination.
The physical & chemical purity of solutes used for sterile preparations
should be considered. For a few substances ex – Vitamin-C, calcium
gluconate special parenteral grades are available.
4) Added substances – It includes solubilisers, antioxidants, chelating
agents, buffers, tonicity builders, antibacterial agents, hydrolysis
inhibitors, antifoaming agents.
Common excipients used in parenterals
Concentration range (%)
Anti microbial preservatives
a) Benzyl alcohol
b) Phenyl mercuric nitrate
c) Thimerosal
d) Propyl paraben
0.5 – 10.0
Solubilisers, wetting agents/emulsifiers
a) Dimethyl acetamide
b) Ethanol
c) Glycerol
d) PEG 300
0.61 – 49.0
a) Acetic acid
b) Citric acid
c) Maleic acid
d) Lactic acid
Tonicity modifiers
a) Lactose
b) Mannitol
c) Sorbitol
d) Nacl
Common excipients used in parenterals
Concentration range
Suspending agents
a) Gelatin
b) Pectin
c) PEG 4000
Anti oxidants
a) Ascorbic acid
b) Thiourea
c) BHT
Local Anaesthetics
a) Procaine Hcl
b) Benzyl alcohol
a) Niacin
b) Sodium caprylate
c) Glycine
a) EDTA disodium
b) EDTA tetrasodium
Isotonicity & method of adjustments
Biologic systems are compatible with solutions having similar osmotic
pressures, that is an equivalent no.of dissolved species. For example
RBC’s, blood plasma and 0.9% Nacl solution contains approx the same
no.of solute particles per unit volume and are termed iso-osmotic &
Compounds contributing to the isotonicity of a product reduce the pain of
injection in areas with nerve endings. Buffers may serve as tonicity
contributors as well as stabilisers for pH.
An Osmol (Osm) is related to a mole (gm mol wt) of the molecules or
ions in solution. One mole of glucose (180 g) dissolved in 1000 g of
water has an osmolality of 1 Osm or 1000 mOsm/kg of water. One mole
of Nacl (23+35.5=58.5 g) dissolved in 1000 g of water has an osmolality
of almost 2000 mOsm, since Nacl dissociates into almost 2 particles per
molecule. In other words, 1 molal solution of Nacl is equivalent to 2 molal
solution of dextrose
Normal serum osmolality values are in the vicinity of 285 mOsm/kg (often
expressed as 285 mOsm/L), ranges may include values from about 275300 mOsm/L. Pharmaceuticals should be close to this value to minimise
discomfort on application to the eyes/nose on application.
Method for calculating isotonicity
A sodium chloride (Nacl) equivalent is the amount of Nacl that is osmotically
equivalent to 1 gm of drug. For example the Nacl equivalent of ephedrine
sulfate is 0.23, that is 1gm of ephedrine sulfate is equivalent to 0.23 gm of
Q1) How much Nacl is required to make the following prescription isotonic?
Rx – Ephedrine sulfate 2%, sterile WFI – q.s 30 ml, make isotonic with Nacl.
a) 30 ml * 0.009 = 0.270 g Nacl is required.
b) 30 ml* 0.02 = 0.6 g ephedrine sulfate is to be present
c) 0.6 g* 0.23 = 0.138 g is the quantity of Nacl represented by ephedrine
d) Since 0.270 g Nacl is required if only Nacl is used & quantity of Nacl that
is equivalent to 0.6 g of ephedrine sulfate is 0.138 g, then 0.270-0.138 =
0.132 g of Nacl required to render solution isotonic.
e) Therefore the solution requires ephedrine sulfate 0.6 g, Nacl 0.132 g and
sufficient sterile WFI to make 30 ml.
Small & Large Volume Parenterals
The term Small Volume Parenteral(SVP) has been officially defined by USP
as “an injection that is packaged in containers labeled as containing 100ml or
less” & Large Volume Parenteral(LVP) applies to injection that is intended for
IV use & packaged in containers holding 100 ml or more (1 litre).
The term LVP means a terminally sterilised aqueous drug product packaged
in a single-dose container with a capacity of more than 100ml intended for
use in man.
Sterile liquid products are classified as SVP’s & LVP’s.
The SVP’s includes pharmaceutical products (otic, ophthalmic & parenterals)
Diagnostic agents, allergenic extracts ,radiopharmaceuticals & biologicals.
The parenteral preparations may be solutions, suspensions, emulsions and
powder for reconstitution.
The LVP’s includes blood collecting units with anticoagulants, peritoneal
dialysates, irrigating solutions, diagnostic agents & IV fluids (solutions &
Differences between SVP & LVP
Small Volume Parenterals
Large Volume Parenterals (LVP)
SVP’s are sterile, pyrogen free
injectable products that are
packaged in vol’s up to 100 ml
LVP’s are sterile, pyrogen free injectable
products that are packaged in vol’s more
than 100 ml (1litre)
Some SVP aqueous solutions
can be administered only by IV
route because of local irritation
LVP’s are administered by intra or extra
vascular routes depending on
SVP’s are usually packed in
vials, ampoules of small sizes
LVP’s are packed in large containers
(glass/plastic of 1 litre capacity)
SVP’s include drugs in
suspension, emulsion, freeze
dried product or powder for
reconstitution. The other
products include biological &
diagnostic agents, allergenic
extracts, radiopharmaceuticals,
dental products, liposomes &
lipids etc
LVP’s includes saline solutions, dextrose
solution, ringers solutions, peritoneal
dialysates, irrigating solutions, diagnostic
agents & blood collecting unit with
Manufacture of SVP’s
1) Planning & scheduling of functions- 4 groups of personnels were involved
a) material management b) personnel management c) equipment & facilities
maintenance d) documentation control.
2) Material management – A group of personnel(s) are responsible for providing
materials necessary to manufacture the product.
3) Personnel management – Appointment of a properly motivated production
staff who will be given training to perform their job.
4) Documentation control – It is the control & verification of critical activities in
a pharmaceutical process production & control cycle.
Examples of documents to be maintained are as follows –
Master file
Batch records
Standard Operating Procedures (SOP’s)
Validation records
Environmental record
Stability records
Process logs & material logs
Complaint files, returned good records
Retained sample storage area records
Manufacture of SVP’s
5) Equipment & facilities management – There are several types of
equipment that are used in overall processing of SVP’s. The examples are
Washing equipment (glass, plastic & rubber components)
Mixing equipment to manufacture the bulk product
Filtering equipment to clarify & or sterilise product
Storage tanks to hold the bulk product prior to sub division
Filling or subdividing equipment
Stoppering & or scaling equipment
Terminal sterilisation equipment.
6) Preparation of facilities – a) cleaning of service areas b) preparation
of clean room areas c) preparation of sterile room d) preparation of
7) Preparation of packaging components – A sterile package consist of
primary & secondary packaging components. Examples of primary
packaging components are ampoules, vials, syringes, syringe cartridges,
squeeze bottles & rubber/plastic stoppers. A box or a shrink wrap is an
secondary packaging components
Production facilities for an aseptic processing of parenterals
The functional parenteral production areas involved are
Warehousing or procurement.
Compounding or formulation.
Materials (containers, closures & equipment).
Preparation area.
Filtration & sterile receiving area.
Aseptic filling.
Lyophilisation & packaging.
The design & control of an aseptic area is directed towards reducing the
presence of these contaminants (dust, lint, microbes, suspended
particles in air) so that they are no longer a hazard to aseptic filling.
Air cleaning – Since air is one of the potential source of contaminants in
clean rooms, special attention must be given to air being drawn into clean
rooms by heating, ventilation & air conditioning (HVAC) systems.
Air control in sterile area
Fresh outside or recycled air must be 1st filtered to remove particulate
matter. A spun glass, cloth or shredded polyethylene filter may be used for
preliminary cleaning operations.
To remove finer debris down to sub micron range, including microbes, a
HEPA filter, defined atleast 99.97% efficient in removing particles of 0.3µm
size & larger & composed of glass fibers & fillers or electrostatic
precipitators, can be employed. Air passing thru these units can be rendered
virtually free from foreign matter.
Blowers should be installed in the air ventilation system upstream to the
filters so that all dirt producing devices are ahead of the filters. The clean air
is normally distributed to the required areas by means of metal (stainless
steel) ducts.
The clean aseptic air is distributed in such a manner that it flows into the
maximum security room at the greatest volume flow rate thereby producing a
positive pressure in these areas. This prevents unclean air from rushing into
the aseptic area thru cracks, temporarily opened doors, or other openings.
A relatively new air control system based on laminar flow principles has
improved the potential for environmental control of aseptic areas. Currently, it
could able to achieve a class 100 clean room.
A class 100 clean room is defined as a room in which the particle count in
the air is NMT 100 per cubic foot of 0.5µm & larger in size. HEPA filtered air
is blown evenly out of entire back or top of a work bench or entire side or
ceiling of a room. The air flow must be uniform in velocity & direction
throughout any given cross section of the area, being exhausted from
opposite side.
The air velocity employed should be 100±20 ft/min. Contamination is
controlled because it is swept away with the air flow. The vertical flow from
ceiling mounted HEPA filter units, is utilised to protect critical sections of
processing lines & most frequently for work benches.
Although class 100 work environment are normally specified for most
critical aseptic & or clean operations, achieving such levels of cleanliness is
expensive & requires effective maintenance & monitoring.
A class 10,000 room is one in which the particle count is not more than
10,000 per cubic foot of 0.5µm & larger in size. Such a cleanliness level is
considered suitable for buffer areas around class 100 work sites in which
operations such as handling, precleaned containers, process filtration &
aseptic gowning of personnel may be performed.
Biologic evaluation methods used includes settling & surface contact
nutrient agar plate, air impingement on nutrient media, membrane filtration,
electronic particle counters etc.
Clean room classified areas for parenterals
society of Pharm
engg description
Max no.of
particles per
cubic meter
Max no.of
particles per
cubic meter
Aseptic areas & facilities for parenterals
The aseptic area requires construction features designed for maximum
microbial & particulate control. The ceiling, walls & floor must be sealed so
that they may be washed & sanitised with a disinfectant, as needed.
All light fixtures, utility service lines & ventilation fixtures should be
recassed in walls/ceiling to eliminate ledges, joints & other locations for
accumulation of dust & air.
The tanks containing compounded product should remain outside aseptic
filling area & product fed into area thru hose lines. Proper sanitation is
required if the tanks must be moved in.
Large mechanical equipment that is located in aseptic area should be
housed as within stainless steel cabinet to seal the operating parts & their
dirt producing tendencies from aseptic environment.
Aseptic area & facilities for parenterals
Personnel entering the aseptic area should enter only thru an airlock. They
should be attired in sterile coveralls with sterile hats, masks, goggles & foot
covers. Movement within the room should be minimal & in & out movement
rigidly be restricted during filling procedure.
Aseptic area operators should be given formal training in the principles of
aseptic processing, fresh, sterile uniforms should be used after every break
period or whenever the individual returns to aseptic area.
Gowning rooms should be designed to enhance pre gowning and gowning
procedures by trained operators so that it is possible to ensure continued
sterility of exterior surfaces of sterile gowning components. De-gowning
should be performed in separate exit room.
Formulation of parenterals
The preparation of a parenteral solution involves the dissolution of all the
ingredients into an appropriate solvent system. The most common solvent is
water. The cosolvents such as aqueous/glycol mixtures to improve the
solubility. Occasionally, non aqueous systems such as vegetable oils are
used when aqueous & cosolvent systems are inadequate to dissolve active
A sterile solution may contain one or more following additives
a) Osmotic pressure adjusters – NaCl, mannitol.
b) Bacteriostatic agents – Benzyl alcohol.
c) Buffering agents – Phosphates, acetates & citrates.
d) Antioxidants – Bisulfite, ascorbate & citrate.
e) Chelates – EDTA to sequester heavy metals which catalyse degradation.
In case of formulating a new compound, in formation related to basic
properties such as mol.wt, solubility, purity, colligative properties, chemical
reactivity etc to be considered.
Inert gases have been used to displace oxygen from a solution & reduce
the possibility of oxidative changes in the formulation. Inert gases may be
used to stabilise solutions.
Formulation of parenterals
Operation-I (Non sterile)
1) Place WFI into a clean, vented, glass lined/stainless steel pressure tank.
A starting volume in excess of 10% of final volume is recommended to
cover losses due to evaporation during heating. Seal the pressure tank.
2) Heat WFI to 121 deg C & maintain for 20 min while gradually releasing
tank pressure. Then cool to 60 deg C.
3) Remove & place in a separate vented SS or glass container of suitable
capacity a qty of WFI equal to about 30% of final formula volume & save
for final vol adjustment.
4) To remaining WFI (at 60 deg C), from step-2, add & dissolve with stirring
to monobasic & dibasic sod phosphate. Care must be taken that
phosphate salts are dissolved.
5) Allow the solution from step-4 to cool to RT (25-30 deg C), then add and
dissolve with stirring water soluble drug & preservative, check the pH of
solution if required adjust to 6.8-7.0 with approx 1N NaoH solution.
6) Bring the bulk to final volume with WFI & mix well.
Formulation of parenterals
Operation-II (Sterilisation)
1) Sterilise the bulk solution from operation-1, step 6, by filtration thru a
sterile sterilising membrane, with an appropriate non shedding
preclarification filter.
2) Collect the sterile filtrate directly from sterilising membrane via sterile
tubing & siphon into a sterile, clean, closed, vented, SS tank or glass
Operation-III (Sterile subdivision)
1) Aseptically subdivide sterile bulk solution into an appropriate sterile
2) Aseptically apply sterilised closure systems to container & seal.
3) Sample across filtering operation at intervals determined by QC
standards for sterility tests & vol fill checks.
4) Visually inspect all units for defects & particulate against a well lighted
black & white background.
5) Submit samples to QC lab for release assays.
Lyophilisation & preparation of sterile powders
Injections are also packaged as dry solids rather than in conjuction with
solvent or vehicle because therapeutic agent is unstable in the presence
of liquid component. These dry powders are packaged in the final
container to be reconstituted, generally to a solution or less frequently a
suspension. The method of sterilisation of powder may be dry heat or
other appropriate method.
Antibiotics are prepared industrially in large fermentation tanks. Sometimes
liquid is packaged with dry powder for use at the time of reconstitution.
This liquid is sterile & may contain some of the desired additives such as
Lyophilisation (freeze dried products) – Solutions intended to be freeze
dried must be aqueous, for the drying process involves removal of water
by sublimation. The formulation must reflect the characteristics to be
imparted to the solid residue (cake) after drying & those required of the
solution after reconstitution at the time of use. The characteristics
required of a good cake are 1) A uniform colour & texture 2) A supporting
matrix of solids sufficient to maintain essentially the original volume after
drying and 3) Sufficient strength to prevent crumbling during storage.
Lyophilisation & preparation of sterile powders
 The % of solids in the frozen plug is between 2 & 25%. When organic
substances such as mannitol, sorbitol, sucrose & gelatin are used to provide
solids for the cake, care must be taken during heating, particularly during
the terminal stages of drying, to avoid discoloration of cake by charing.
 Added substances required in the formulation must not be volatile under the
conditions of drying, therefore antibacterial agents such as phenol,
chlorobutanol & benzyl alcohol must not be used. Suspensions of drugs for
parenteral use may be prepared by reducing the drug to a very fine powder
with a ball mill, microniser, colloid mill or other appropriate equipment & then
suspending the material in a liquid in which it is insoluble.
 It is frequently necessary to sterilise separately the individual components of
a suspension before combining them, as the integrity of the suspension is
destroyed by autoclaving. It may alter the viscosity of product, affecting the
suspending ability of the vehicle, or change the particle size of suspended
particles, altering both pharmaceutical & therapeutic characteristics. If a
suspension remains unaltered by autoclaving this method is generally
employed to sterilise the final product.
Containers for parenterals
1) Glass – It includes ampoules, vials, 1 litre bottle or more capacity
2) Plastic – 1 litre capacity or more
3) Rubber – closure material sealed with aluminium
GLASS– The glass used in manufacture of such containers (ampoules,vials,
bottles etc) complies with one of the requirements for hydrolytic resistance.
There are 3 types of glass used, the types are distinguished by resistance to
water attack of new glass containers, the degree of attack being determined
by amount of alkali released from the glass under specified conditions.
a)Type-I (Neutral glass) – It offers a high hydrolytic resistance due to
chemical composition of glass. It is also called borosilicate glass.
b)Type-II (treated soda lime glass) – It has a high hydrolytic resistance due
to an appropriate surface treatment.
c)Type-III (regular soda lime glass)- It offers only a moderate hydrolytic
resistance & should be used only for non-aqueous liquid preparations or for
powders for injection or for injectable preparations where adequate suitability
tests have indicated for other dosage forms.
d) NP – General purpose Not for Parenteral soda lime glass.
Containers for parenterals
PLASTIC: The principal ingredient of various plastic materials used for
container is thermoplastic polymer. All of the polymeric materials except
low density polyethylene & polystyrene can be autoclaved if they have
been formulated with low amount of plasticizers.
Plastic containers are used mainly because of light in weight, non
breakable, low toxicity & low reactivity with products. Polyethylene and
Polypropylene are the most commonly used polymer. The USP has
provided test procedures for evaluating toxicity of plastic materials. The
test consist of 3 phases
a) Implanting small pieces of plastic material (IM route) in rabbits
b) Injecting eluates using Nacl injection, with & without alcohol,
intravenously in mice & injecting eluates using PEG 400 & sesame oil
intraperitoneally in mice
c) Injecting all 4 eluates subcutaneously in rabbits. The reaction from test
samples must not be greater than non reactive control samples.
Closures for Parenterals
Rubber Closures: These are used to seal the openings of cartridges, vials
and bottles providing a material soft & elastic enough to permit entry &
withdrawl of a hypodermic needle without loss of integrity of sealed
Composition of Rubber Closure: It is made up of natural rubber (latex) &
or a synthetic polymer, a vulcanising agent (sulfur), an accelerator (2mercaptobenzothiazole), an activator (Zno), filler (carbon black/limestone)
and other ingredients such as antioxidants & lubricants.
The compatibility of rubber closures with the drug product is assessed by
placing the closure in contact with the drug product & maintaining the
samples at elevated temperature levels for planned periods of time. At
prescribed intervals, samples are examined for quantitative and
qualitative evidence of chemical/physical change either in the closure or
in the product.
Physical Characteristics: Several properties of rubber closures are
significant, particularly elastic, hardness & porosity. Rubber closures must
be sufficiently elastic to provide a snug fit between the closure & the neck
Closures for Parenterals
and lip of glass containers. The physical shapes of closures vary with their
intended use. The common shapes are flanged closure (center), slotted
for freeze dried products, punctured for attachment of adapters for
infusion sets & the plunger type for use with cartridge.
Testing of Rubber Closure: The USP describes physico chemical tests on
aqueous extracts include pH, turbidity, residue on drying, Iodine number &
heavy metals content. The biologic tests on saline, PEG 400 &
cottonseed oil extracts include acute & chronic toxicity in mice & rabbits.
Test for Hydrolytic resistance (Limits for alkalinity) for glass containers
The selected no.of containers should be rinsed atleast twice with water at RT.
Just before the test rinse each container with freshly prepared distilled water. Fill
the containers to the brim with freshly prepared distilled water, empty them &
determine the average over flow volume.
Fill ampoules with freshly preparaed distilled water to the max volume & seal
them by fusion. Fill bottles/vials to 90% of their calculated overflow volume &
cover with borosilicate glass dishes/aluminium foil previously rinsed with freshly
prepared distilled water.
Place the containers in an autoclave containing water so that they remain clear
of water. Close the autoclave, displace the air by passage of steam for 10 mins,
raise the temperature from 100 to 121 deg C over 20 mins, maintain the
temperature of 121 deg C for 60 mins & reduce the temperature from 121 to 100
deg C over 40 mins, venting to prevent vacuum.
Remove the containers from autoclave & cool them in a bath of running tap
water. Carry out the following titration within 1 hr of removing the containers
from autoclave. Combine the liquids from the containers being examined,
measure the vol of test solution & add 0.15 ml of methyl red solution for each 50
ml of liquid, titrate with 0.01M Hcl taking as the end point the colour obtained by
repeating the operation using same volume of freshly prepared distilled water.
Test for Hydrolytic resistance (Limits for alkalinity) for glass containers
The difference between the titrations represents the vol of 0.01M Hcl
required by the test solution. Calculate the volume of 0.01M Hcl required for
each 100 ml of test solution if necessary. The result is NMT value stated in
an oven at 130 deg C for ½ hr. Cool, add to the residue 10 ml of hydrazinemolybdate reagent, swirl to dissolve & heat under reflux on a water bath for
20 mins.
Cool to RT. Determine the absorbance of resulting solution at max at about
840 nm, using 10 ml of hydrazine-molybdate reagent as blank. The
absorbance of test solution does not exceed the absorbance obtained by
repeating the determination using 0.1 ml of arsenic std soln (10 ppm As)in
place of test solution (0.1 ppm)
Test for Sterility (as per IP)
It is intended for detecting the presence of vianle forms of microorganisms
in parenteral preparations. The tests are based upon the principle that is
microbes are placed in a medium which provides nutritive material & water
kept at favourable temperature, the organisms will grow & their presence can
be indicated by a turbidity in the originally clear medium.
The probability of detecting viable microbes in the tests for sterility
increases with the number present in a given amount of preparation being
examined & varies according to the species of microbes present. Very low
levels of contamination can’t be detected on the basis of random sampling of
a batch.
A batch may be defined for the purpose of these tests as homogeneous
collection of sealed containers prepared in such a manner that the risk of
contamination is the same for each of the units in it.
The tests for sterility are designed to reveal the presence of microbes in
the samples used in the tests. Interpretation of results is based on
assumption that contents of every container in the batch, had they been
tested, would also have complied with the tests. Since every container can’t
be tested, a sufficient no.of containers should be examined to give a suitable
degree of confidence in the results of the tests.
Test for Sterility (as per IP)
The official USP methods include direct inoculation test & filtration test
methods (using membrane filtration). The false negative results of a direct
inoculation test also may occur as a result of antibacterial activity inherent in
the product. A false negative results also may be obtained if the microbial
population is so small that the inoculum taken from the product does not
contain a microorganism.
A false positive test result could be caused by inadvertent contamination
during the test. Such false results can be eliminated by the use of carefully &
adequately trained personnel working in a properly controlled environment.
Methods of Sterilisation –
1) Thermal methods – Dry heat, Moist heat (using steam).
2) Non thermal methods – UV light, ionisation radiations.
3) Chemical methods
a) Gaseous sterilisation – Ethylene oxide, Beta propiolactone
4) Terminal sterilisation using autoclave
Filling & Sealing of Parenterals
Filling equipment for liquids – A measured vol.of liquid is forced through
the orifice of a delivery tube designed to enter the constricted opening of a
container. The size of the delivery tube is governed by the opening in the
container to be used, the viscosity & density of the liquid & speed of delivery
The tube must freely enter the neck of the container & deliver the liquid
deep enough to permit air to escape without sweeping the entering liquid into
the neck or out of the container. To reduce the resistance to the flow of liquid,
the tube should have the max possible diameter. Excessive delivery force
causes splashing of the liquid & troublesome foaming, if the liquid has a low
surface tension.
Filling machines should be designed so that the parts through which the
liquid flows can be easily demounted for cleaning & sterilisation. These parts
should be constructed of non-reactive materials such as borosilicate
glass/SS. Syringes are usually made of SS when the pressure required for
delivery of viscous liquid or large volumes would be unsafe for glass
Filling & Sealing of Parenterals
The pressure pump filler often is operated semi automatically & differs from
gravity filler principally in that the liquid is under pressure. It is usually
equipped with an overflow tube connected to a receiver to prevent excess
filling of the container.
Vacuum filling is commonly used in tester filling lines for large volume of
liquids because it is more adaptable to automation. A vacuum is produced in
a bottle when a nozzle gasket makes a seal against the lip of the bottle to be
 The vacuum draws the liquid from a reservoir through the delivery tube
into the bottle, when the liquid level reaches the level of adjustable overflow
tube, the seal is mechanically loosened & vacuum is released.
Filling equipment for solids – Sterile solids such as antibiotics are more
difficult to subdivide accurately & precisely into individual dose containers
than are liquids. The rate of flow of solid material tends to be slow & irregular,
particularly if finely powdered. Small, granular particles flow must evenly.
Filling & Sealing of Parenterals
Sterile solids can be subdivided into containers by individual weighing. The
operator can use a scoop that holds a vol approx equal to the weight
required, but the quantity filled into the container is finally weighed on a
One type of machine for delivering measured quantities of free-flowing
material employs an auger in the stem of funnel shaped hopper. The size &
rotation of auger can be adjusted to deliver a regulated vol of granular
material from the funnel stem into the container.
In another filling machine, an adjustable cavity in the rim of the filling wheel
is filled by vacuum as the wheel passes under the hopper. The contents are
held by vacuum until the cavity is inverted over the container, when a jet of
sterile air discharge the dry solids. This machine dispenses only dry solids
that flow less freely than those of other machines presently available.
Sealing of parenteral products – Containers should be sealed in the
aseptic area immediately adjacent to the filling machine. In addition to
retaining the contents of a sterile product, sealing of containers assures the
users that it has not been opened.
Filling & Sealing of Parenterals
Sealing of ampoules – It may be closed by melting a portion of the glass
of neck to form either bead seals (tip-seals) or pull seals. Tip seals are made
by melting sufficient glass at the tip of ampoule neck to form a bead of glass
& close the opening. Pull-seals are made by heating the neck of rotating
ampoule below the tip, then pulling the tip away to form a small, twisted
capillary just prior to being melt closed.
The heating with a high temperature gas oxygen flame must be even &
carefully controlled to avoid gas distortion of the seal. Excessive heating of
air & gases in the neck causes expansion against the soft glass with the
formation of fragile bubbles at the point of seal. Pull sealing is a slower
process & more reliable than tip sealing. Powder ampoules or other types
having a wide opening must be sealed by pull-sealing.
It is some times necessary to displace the air in the space within the
ampoule above the product to prevent decomposition. This may be done by
introducing a stream of inert gas (N2 or CO2) during/after filling with the
product. Immediately thereafter the ampoule is sealed before the gas can
diffuse to the outside.
Sealing of ampoules
Sealing bottles, cartridges & vials – When closures are to be inserted by
machines, the surface of the closure is usually halogenated/coated with
silicone to reduce friction. Aluminium caps are used to hold rubber closures
in place. Single caps may have a permanent center hole or a center that is
torn away at the time of use to expose the rubber closure.
Double aluminium caps usually have a inner cap with a permanent center
hole which in use is exposed when the entire outer cap is torn off. The triple
aluminium caps are used for large bottles with rubber closures having
permanent holes for attachment to administration sets.
Evaluation (QC Tests) for Parenterals
The 3 general areas of QC are incoming stock, manufacturing & finished
products. It is also necessary to perform microbial load (bioburden) tests to
determine the no & types of microbes present.
In addition to the usual chemical & biologic tests, a sterile product is
subjected to a leaker test, a clarity test, a pyrogen test & a sterility test. The
production control includes all of the final assays & tests to which the product
is subjected.
Leaker test - The leaker test is intended to detect incompletely sealed
ampoules so that they may be discarded. Tip-sealed ampoules are more
likely to be incompletely sealed than that of pull sealed. In addition, small
cracks may occur around the seal or at the base of ampoule as a result
of improper handling.
Leakers are detected by producing a negative pressure within an
incompletely sealed ampoule, usually in a vacuum chamber, while the
ampoule is entirely submerged in a deeply coloured dye solution (usually
0.5-1.0% methylene blue). Subsequently atmospheric pressure then
causes the dye to penetrate an opening being visible after the ampoule
has been washed externally clear it of dye.
QC tests for parenterals
The vacuum (27 inches Hg or more) should be sharply released after 30
min. Only a tiny drop of dye may penetrate a small opening. The detection of
leaker is more effective when the ampoules are immersed in a bath of dye
during the autoclaving cycle.
Another test is to apply a spark tester probe to the outside of bottle, moving
from the liquid layer into the air space. A blue spark discharge occurs if the
air space is evacuated.
2) Clarity test – The USP states that good pharmaceutical practice requires
that all containers to be visually inspected & that any with visible particles to
be discarded. In addition, for LVP (infusions), the USP has established a limit
of 50 particles of 10µm & larger & 5 particles of 25µm & larger per ml.
Suspensions, emulsions, or dry solids, in addition to solutions should be
compounded & processed under clean conditions to minimise the presence
of foreign particles.
The visual inspection of a product container is done by individual human
inspection of each externally clean container under a good light, baffled
against reflection into the eyes & viewed against a black & white
background, with the contents set in motion with a swirling action.
QC tests for parenterals
A moving particle is much easier to see than a stationary one, but care
should be taken to avoid introducing air bubbles, which are difficult to
distinguish from dust particles.To see heavy particles it is necessary to invert
the container as a final step in inspection.
Instrumental methods of evaluation for particulate matter in liquids utilising
the principles of light scattering, light absorption & electrical resistance have
been used to obtain particle counts & size distribution. A method utilising
video image projection coupled with electronic circuitry detects moving
particles with out destruction of the product unit.
3) Pyrogen test (Bacterial endotoxin test) – The presence of pyrogen in
parenteral preparations is detected by a qualitative biologic test based on the
fever response in rabbits. If a pyrogenic substance is injected into the vein of
a rabbit, an elevation of temperature occurs within a period of 3hrs.
The housing conditions & handling are critical to obtain a consistent results
with rabbits in the test. Because of this the use of rectal thermometers has
largely been replaced by rectal thermocouples, which remain in place
throughout the test eliminating the handling of rabbits for individual
temperature readings.
QC tests for Parenterals
Recently, an invitro test method for pyrogens has been developed utilising
the gelling property of the lysate of amebocytes of limulus polyphemus
(horse shoe crab). In the presence of pyrogenic endotoxins from gram
negative bacteria, a firm gel is formed within 60 min when incubated at 37
deg C.
Although only endotoxins from gram negative bacteria react in this way,
they constitute the majority & the most potent of contaminating pyrogens.
The LAL (Limulus Amebocyte Lysate) test is 5-10 times more sensitive than
rabbit tests & by use of serial dilutions has been shown to be
4) Other test – Sterility tests
a) Direct inoculation method
b) Membrane filtration method
Parenteral filling & sealing equipments
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