Powders and Granules
Dr. Basavaraj K. Nanjwade
M. Pharm., Ph. D
Department of Pharmaceutics
Faculty of Pharmacy
Omer Al-Mukhtar University
Tobruk, Libya.
E-mail: nanjwadebk@gmail.com
2014/06/08
Faculty of Pharmacy, Omer Al-Mukhtar University,
Tobruk, Libya.
1
CONTENTS
1.
2.
3.
4.
5.
6.
7.
8.
9.
Definition, advantages, size shape, storage.
Hard gelatin capsules (shell manufacture filling).
Soft gelatin capsules (manufacturing and filling).
Sustained release and enteric coated capsules.
Formulation factors affecting bioavailability.
Microencapsulation (Introduction, advantages).
Coacervation phase separation technique.
Pan coating, electrostatic deposition, spry drying.
References.
2014/06/08
Faculty of Pharmacy, Omer Al-Mukhtar University,
Tobruk, Libya.
2
Definition of Powders
• A pharmaceutical powder is a mixture of finely
divided drug and/or chemicals in dry form.
• Powders are solid dosage form of medicament which
are meant for internal and external use.
• They are available in crystalline or amorphous form.
• The particle size of powder plays an important role in
physical, chemical and biological properties of the
dosage forms.
2014/06/08
Faculty of Pharmacy, Omer Al-Mukhtar University,
Tobruk, Libya.
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Definition of Granules
• Granulation is the process in which primary powder
particles are made to adhere
to form larger,
multiparticle entities called granules.
• Pharmaceutical granules typically have a size range
between 0.2 and 0.4 mm, depending on their
subsequent use.
• In the majority of cases this will be in the production
of tablets or capsules, when granules will be made as
an intermediate product and have a typical size range
between 0.2 and 0.5 mm.
2014/06/08
Faculty of Pharmacy, Omer Al-Mukhtar University,
Tobruk, Libya.
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Advantages of
Powders and Granules
• Solid preparations are more chemically stable than
liquid ones.
• Powders and granules are a convenient form in which
to dispense drugs with a large dose.
• Orally administered powders and granules of soluble
medicaments have a faster dissolution rate than
tablets or capsules, as these must first disintegrate
before the drug dissolves.
2014/06/08
Faculty of Pharmacy, Omer Al-Mukhtar University,
Tobruk, Libya.
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Particle Size
Powders and Granules
•
Particle size is characterized using these terms :
i. Very coarse (#8)
ii. Coarse (#20)
iii. Moderately coarse (#40)
iv. Fine (#60)
v. Very fine (#80)
2014/06/08
Faculty of Pharmacy, Omer Al-Mukhtar University,
Tobruk, Libya.
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Particle Shape
Powders and Granules
2014/06/08
Faculty of Pharmacy, Omer Al-Mukhtar University,
Tobruk, Libya.
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Different shapes of crystals
2014/06/08
Faculty of Pharmacy, Omer Al-Mukhtar University,
Tobruk, Libya.
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Hard gelatin capsules
(shell manufacture filling)
• These are used for administration of solid medicaments.
• The capsule shell is prepared from gelatin, colour and
titanium dioxide to make it opaque.
• It consists of two parts i.e. body and cap.
• The powdered material is filled into the cylindrical
body of the capsule and then the cap is placed over it.
• The empty capsules are available in various sizes.
• They are numbered according to the capacity of the
capsules.
• The number starts from 000 and goes up to 5.
2014/06/08
Faculty of Pharmacy, Omer Al-Mukhtar University,
Tobruk, Libya.
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Hard gelatin capsules
(shell manufacture filling)
2014/06/08
Capsule number
Approximate capacity in mg
000
950
00
650
0
450
1
300
2
250
3
200
4
150
5
100
Faculty of Pharmacy, Omer Al-Mukhtar University,
Tobruk, Libya.
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Hard gelatin capsules
(shell manufacture filling)
2014/06/08
Faculty of Pharmacy, Omer Al-Mukhtar University,
Tobruk, Libya.
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Methods of filling the hard
gelatin capsules
• The capsules can be filled either by hand or by a semiautomatic device or by an automatic filling machine.
• Capsule filling machine (Hand operated) It consists of:1. A bed having 200-300 holes
2. A loading tray having 200-300 holes
3. A powder tray
4. A pin plate having 200-300 pins
5. A sealing plate having a rubber top
6. A lever
7. A cam handle
2014/06/08
Faculty of Pharmacy, Omer Al-Mukhtar University,
Tobruk, Libya.
12
Soft gelatin capsules
(manufacturing and filling)
• These are used for administration of liquid
medicaments. Soft gelatin capsules are available in
round, oval and tube like shapes.
• They are made from gelatin. The gelatin is plasticized
by the addition of glycerin and sorbitol etc.
• The soft gelatin shell may contain a preservative to
prevent the growth of fungi.
• They are used to enclose liquid medicaments-oils,
suspensions, food concentrates and ophthalmic
products.
2014/06/08
Faculty of Pharmacy, Omer Al-Mukhtar University,
Tobruk, Libya.
13
Soft gelatin capsules
(manufacturing and filling)
2014/06/08
Faculty of Pharmacy, Omer Al-Mukhtar University,
Tobruk, Libya.
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Method of filling of soft
gelatin capsules
• Soft gelatin capsules are generally filled mechanically.
• The manufacturing of the capsule shell and the filling of
the medicament take place simultaneously. Nowadays, a
rotary machine is used for this purpose.
• Rotary die machine, the soft gelatin capsules are prepared
and then filled immediately with the liquid medicaments.
• The machine consists of two hoppers.
• Liquid gelatin mixture is placed in one hopper and the
liquid medicament in the other hopper.
• There are two rotating dies which rotate in opposite
directions.
2014/06/08
Faculty of Pharmacy, Omer Al-Mukhtar University,
Tobruk, Libya.
15
Sustained release capsules
• In order to maintain a proper blood concentration of the
medicament and reducing the number of doses per day,
a capsule, containing numerous coated pellets, is
administered that release the drug successively over a
long period.
• The finely powdered drug is first converted into pellets.
• These pellets are treated with protective coatings that
delay the release of the drug.
• The batches of pellets are mixed thoroughly and
suitable doses are filled into capsules.
2014/06/08
Faculty of Pharmacy, Omer Al-Mukhtar University,
Tobruk, Libya.
16
Enteric coated capsules
• These capsules do not disintegrate in the stomach
(acid medium) but break-up in the intestine (alkaline
medium).
• A special type of treatment or coating is given to the
capsules so that these can pass unchanged through the
stomach but get disintegrated in the intestine.
• On a commercial scale, a coating of cellacephate
(cellulose acetate phthalate) and mixtures of waxes
with fatty acids or their esters is given.
2014/06/08
Faculty of Pharmacy, Omer Al-Mukhtar University,
Tobruk, Libya.
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Enteric coated capsules
• The following categories of drugs need enteric
coatings.
1. Drugs which cause irritation to the gastric mucosa
and lead to nausea and vomiting.
2. Drugs which are destroyed by the gastric juices.
3. Drugs which are specially intended to act in the
intestine e.g. amoebicides and anthelminitics.
4. Drugs which are required to produce a delayed
action.
2014/06/08
Faculty of Pharmacy, Omer Al-Mukhtar University,
Tobruk, Libya.
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Formulation factors
affecting bioavailability
• The types of dosage form and its method of preparation or
manufacture can influence bioavailability.
• Particular drug is incorporated and administered in the form
of a solution, a suspension or solid dosage form can
influence its rate and/or extent of absorption from the
gastrointestinal tract.
• The type of oral dosage form will influence the number of
possible intervening steps between administration and the
appearance of dissolved drug in the gastrointestinal fluids.
• Types of dosage form: aqueous solution > aqueous
suspensions > solid dosage forms (e.g. hard gelatin capsules
or tablets).
2014/06/08
Faculty of Pharmacy, Omer Al-Mukhtar University,
Tobruk, Libya.
19
Formulation factors
affecting bioavailability
2014/06/08
Faculty of Pharmacy, Omer Al-Mukhtar
University, Tobruk, Libya.
20
Microencapsulation
(Introduction)
• Microencapsulation is a process or technique by
which thin coating can be applied to small particles of
solids, droplets of liquids or dispersion, thus forming
microcapsules.
• The microcapsules may consist of a single particle or
clusters of particles.
• It differs from other coating methods because
microencapsulation process is used to coat the
particles having a particle size range from several
tenths of a micro to 5000 .
2014/06/08
Faculty of Pharmacy, Omer Al-Mukhtar University,
Tobruk, Libya.
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Microencapsulation
(advantages)
• Advantages of Microencapsulation Process
1. It is used for masking the taste of bitter drugs.
2. It is used for preparing prolonged action dosage
form
3. It is used in modifying the physical characters of a
material required in certain formulations
4. The technique is used to separate an incompatible
material
5. It is used to protect chemicals against moisture and
oxidation.
2014/06/08
Faculty of Pharmacy, Omer Al-Mukhtar University,
Tobruk, Libya.
22
Coacervation
phase separation technique
• Coacervation means the separation of a liquid or phase
when solution of two hydrophilic colloids are mixed under
suitable conditions.
• In this method, the three immiscible phases of core material,
solvent and coating material are formed followed by
deposition of coating material on the core.
• The coating material is dissolved in a suitable solvent and
the core material is uniformly dispersed in the solution of
the coating material.
• Then the coating material is phased out of its solution which
starts getting deposited on the particles of the core material.
2014/06/08
Faculty of Pharmacy, Omer Al-Mukhtar University,
Tobruk, Libya.
23
Pan coating
• In this technique the coating is done in a pan made up
of copper or stainless steel.
• The pan is rotated with the help of an electric motor.
• The tablets to be coated are placed in the pan.
• Hot air is blown in, speed of the pan is adjusted in
such a way that the tablet remain separated from each
other in the pan.
• After coating, polishing is done in a polishing pan,
pan coating technique is used for sugar coating, film
coating and enteric coating.
2014/06/08
Faculty of Pharmacy, Omer Al-Mukhtar University,
Tobruk, Libya.
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Pan coating
2014/06/08
Faculty of Pharmacy, Omer Al-Mukhtar University,
Tobruk, Libya.
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Electrostatic deposition
• The method is useful both for solid particles and liquid
droplets.
• In this process, the core and coating materials are
electrically charged by means of high voltage such as 10,
000 volts etc.
• The core is charged and placed in the coating chamber.
• The coating material is also charged before it is sprayed
as a mist.
• Because the charges are of opposite kind, the coating
material gets deposited on the core due to electrostatic
attraction.
2014/06/08
Faculty of Pharmacy, Omer Al-Mukhtar University,
Tobruk, Libya.
26
Spry drying
• The spray drying provides a large surface area for heat
and mass transfer by atomizing the liquid to small
droplets.
• Sprayed into a stream of hot air, so that each droplet
dries to an individual solid particle.
• Spry drying ensures good air circulation, facilitates heat
and mass transfer and encourages the separation of
dried particles from the moving air by the centrifugal
action.
• The character of the particles is controlled by the
droplet size, and so the type of atomizer is important.
2014/06/08
Faculty of Pharmacy, Omer Al-Mukhtar University,
Tobruk, Libya.
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Spry drying
2014/06/08
Faculty of Pharmacy, Omer Al-Mukhtar University,
Tobruk, Libya.
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THANK YOU
e-mail: nanjwadebk@gmail.com
2014/06/08
Faculty of Pharmacy, Omer Al-Mukhtar University,
Tobruk, Libya.
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