2. Powders
Simple Powders
Definition of powders
Types of powders
Formulation of powders
Methods of preparation
Packaging and labeling of powders
Compound Powders In Bulk
Compound Powders In Single Doses
3. Powder & granules
The term 'powder' when used to
describe a dosage form describes a
formulation in which a drug powder has
been mixed with other powdered
excipients to produce the final product.
A Pharmaceutical powder is a mixture of
finely divided drugs or chemicals in a dry
form meant for internal or external use.
Granules which are used as a dosage
form consist of powder particles that
have been aggregated to form a larger
particle, which is usually 2-4 mm in
diameter.
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4. Advantages of powders DF
Good chemical stability compared with fluids
useful for bulky drugs with large dose, e.g.
indigestion powder.
The smaller particle size of powders causes more
rapid dissolution in body fluids, increases drug
bioavailability, and decreases gastric irritation
compared with tablets
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5. Disadvantages of powders DF
1. Bulk powders are far less convenient for the
patient to carry than a small container of
tablets or capsules,
2. The masking of unpleasant tastes may be a
problem with this type of preparation.
3. Powders are not a suitable method for the
administration of drugs which are inactivated
in, or cause damage to, the stomach; these
should be presented as enteric-coated
4. It is difficult to protect powders containing
hygroscopic, deliquescent (tending to melt or
dissolve in humid environment), or aromatic
materials from decomposition
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6. Types of powders
bulk powders for external use – termed dusting
powders
bulk oral powders
divided powders/individual unit dose powders-
Single Dose
unit dose capsules.
Other preparations which are presented as
powders or granules include:
insufflations for administration to ear, nose or
throat
antibiotic syrups to be reconstituted before use
powders for reconstitution into injections
dry powder inhalers.
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7. Bulk powders for external us
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These are dry, free-flowing preparations consisting
of one or a mixture of finely powdered substances
and intended for external application.
The advantages of dusting powders
They are easy to apply.
They are pleasant to use.
They absorb skin moisture leads to reduced
friction btn skin surfaces
The disadvantages of dusting powders
They may block pores, causing irritation
There is a possibility of contamination
Light fluffy powders may be inhaled by infants,
causing breathing difficulties.
They are not suitable for application to broken
skin.
8. Bulk oral powders
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Bulk oral powders resemble dusting powders with
the exception that they are intended for oral
administration.
The dose to be taken is measured with a 5mL
spoon, stirred into a quantity of water and then
swallowed.
Consequently, this formulation is restricted to use
in preparations consisting of relatively non-potent
medicaments such as Kaolin BP and Magnesium
Trisilicate BP, where such products are intended
for the symptomatic relief of minor ailments
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The advantages of bulk oral powders
dry powders may be more stable than their liquid
equivalent
large doses of bulky powders may be
administered with relative ease (e.g. indigestion
powders)
absorption from the gastrointestinal tract will be
quicker than with capsules or tablets.
The disadvantages of bulk oral powders
the accuracy of dosage is not guaranteed,
therefore it is not a suitable dosage form for
potent medication
the large size container means that they may be
inconvenient to carry
10. Individual unit dose (Divided)
powders
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Single-dose powders usually consist of one or
more powdered active medicaments, together
with an inert diluent, and wrapped as single
doses in white demy paper, folded to a uniform
shape and size.
The disadvantage with bulk oral powders is that the
dosage problem, it is overcome by providing
the patient with a set of separate doses, each
of which has been individually wrapped packets,
cachets, capsules
Traditionally, single doses were wrapped in paper.
Modern packaging materials of foil and plastic
laminates have replaced such paper wrappings
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Advantages
More stable than liquid dosage forms
Accurate dosing flavours
Easy to administer
Small particle size of drug
Acceptable to patients
Disadvantages
May be difficult to swallow
Hard to mask unpleasant
12. Unit dose capsules
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Capsules are a further development from unit
dose powders in that each dose of powder is
enclosed in n edible gelatin capsule, which is
swallowed whole with a water
The powder is not released from its container
until it is in the stomach. This type of presentation
is more convenient for the patient, and is
particularly useful for medicaments which have an
unpleasant taste
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Advantages
Powders show greater stability
than liquid dosage forms
Accurate dosage is possible.
They are easy to administer –
capsules are relatively easy to
swallow (suitable shape and
slippery when moistened).
Unpleasant tastes can be easily
masked.
The release characteristics of the
drugs can be controlled.
The smaller particle size of
powdered drugs leads to more
rapid absorption from the
gastrointestinal tract compared to
tablets.
They are well accepted by patients,
attractive to patients and
convenient to carry
The disadvantages
They may be
difficult to swallow.
Capsules are
unsuitable for very
small children.
Patients with strict
religious beliefs and
vegetarians may
object to the use of
animal gelatin
(although non-animal
gelatin capsules may
be available).
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Insufflations; are medicated
powders which are blown into
body cavities such as the ear,
nose and throat using an
insufflator. It sprays the
powder into a stream of finely
divided particles all over the
site of application
Dry-powder inhalers/Suffs;
The use of dry-powder
systems for pulmonary drug
delivery. Used as
decongestant, bronchodilator
15. Formulation of powders
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Bulking agents- like starch, lactose,
chalk
Absorbent agents; bentonite, kaolin
Adhesives; Aluminium Stearate, Zinc
Stearate
Coloring agents
flavouring and sweetening agents, for
example, may be added to powders for
oral use.
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Preparation of Powders
1- Reduction of particle size using;
trituration, pulverization and levigation.
2- Sieving.
3- Weighing of each ingredient.
4- Mixing
5- Packaging and labeling- packed in air
tight containers, pressurized containers,
plastic or metal
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Zinc Starch and Talc Dusting Powder BPC
Compound Magnesium Trisilicate Oral Powder
BP
