Powders are solid dosage forms where drugs are dispensed in a finely divided state, with or without excipients. They have advantages like faster onset of action compared to other forms but also disadvantages like bitter drugs not being suitable. Powders are prepared through processes like size reduction, weighing ingredients, mixing through methods like spatulation or geometric dilution, and packaging. They are classified based on use and include bulk powders, simple/compound powders, and compressed powders.

1. POWDERS

2. Introduction
• Pharmaceutical powders are solid dosage
forms of medicament in which one or more
drugs are dispensed in finely divided state with
or without excipients.
• They are available in crystalline or amorphous
form.

3. Advantages
• It is used both internally and externally.
• It is more stable than liquid dosage form.
• It is convenient for the physician to prescribe a specific
amount of powder.
• Onset of action is faster as compared to tablet, capsules
because it is easily dissolved in body fluids.
• Easy to carry.
• Easy to administration to the patient orally by dissolving
in suitable liquids.

4. Disadvantage
• Drugs that have bitter taste, nausea and unpleasant taste
cannot be administered in powder form.
• Deliquescent and hygroscopic drugs cannot be dispensed
in powder form they are packed in double wrapping.
• Drugs which get affected by atmospheric condition are
not suitable for dispense.
• Quantity less than 100 mg cannot be weighed
conveniently.

5. Divided powder
Method of preparation
1. Reduction of particle size of all ingredients to the
same range to prevent stratification (separation of the
large and small particles)
2. Sieving
3. Weighing each ingredient
4. Mixing
5. Packaging
• During powdering, weighing and mixing, there is loss of
powder which cannot be avoided. Therefore, while
calculating the quantity of ingredients calculate for one
extra powder than required.

6. 1. Size reduction
• Is the process of reducing large solid units or substance into smaller
unit mass, coarse particles or fine particles. It is also termed
comminution, grinding or pulverization.
• Smaller particle size and increased surface area, leads to: Uniform
distribution of the drug substance in a powder mixture or solid
dosage form to ensure dose to dose content uniformity.
Size reduction on large scale
a. Compression: positive pressure, e.g., nut crusher, ball mill
b. Impact: material is stationary and hit by an object ,e.g., hammer
mill
c. Shear: cutting force, e.g., scissors, colloid mill
d. Attrition: breaking the edges of the solid either by impact or
particle collisions (fluid energy mill and roller mill). Hammer mill

7. 2. Sieving
3. Weighing each ingredient
4. Mixing of powders
• The powders may be mixed by any one of the
following methods: (mixing methods)
Spatulation
Trituration
Geometric dilution
Sifting
Tumbling

8.  Spatulation
• In this method, the mixing of powders is done by the
movement of a spatula throughout the powders on a sheet
of a paper or on a porcelain tile. The method is very useful
in mixing:
a) Small amount of powder
b) Solid substances that liquify or form eutectic mixtures,
when in close and prolonged contact with one another
since very little compression or compact results.
This method is not suitable for large quantities of powders or
for powders containing one or more potent substances
because homogenous blending may not occur.

9. Trituration
• It is used both to reduce particle size and mix powders.
• If particle size reduction is desired along with mixing of
powders, a porcelain mortar with a rough inner surface is
preferred to a glass mortar with a smooth working surface.
A glass mortar may be preferred for chemicals that may
strain a porcelain surface and for simple mixture of
substances without special need for comminution. A glass
mortar cleans more readily after use.

10. Geometric dilution
• The method is used when potent substances are to mixed with a
large amount of diluent. The potent drug is placed upon an
approximately equal amount of the dilute in a mortar and the
substances are slightly mixed by trituration. A second portion of
diluent equal in volume to the powder mixture in the mortar is
added and trituration is repeated. The process is continued,
adding diluent equal in volume to the mixture in the mortar at
each step, until all the diluent is incorporated.

11. • For example, if 100 mg of potent drug is required to be
mixed with 900 mg of lactose, then according to geometric
dilution, the following procedure should be followed:
 100 mg of a potent drug + 100 mg of lactose = 200 mg of mixture
 200 mg of the mixture + 200 mg of lactose= 400 mg of mixture
 400 mg of the mixture + 400 mg of lactose= 800 mg of mixture
 800 mg of the mixture + remaining portion of lactose= 1000 mg of
mixture.
Sifting
• The powders are mixed by passing through sifters. This
process results in a light fluffy product and is generally not
acceptable incorporation of potent drugs into a diluent base.

12. Tumbling
• It is the process of mixing powders in a large container
rotated by an electronic motor. These blenders are widely
employed in industry as large volume powder mixers.

13. 5. Packaging
• Powders may be wrapped in paper or dispensed in
bulk powder in a wide mouth container.
• Wrapping of powders:-White glazed paper is
generally used for wrapping. The wrapping should be
done on a clean tile or large sheet of a glazed paper to
protect the product.

14. CLASSIFICATION OF POWDERS
1. Bulk powder for internal use
2. Bulk powder for external use
3. Simple and compound powder for internal use
4. Powders enclosed in cachets and capsules
5. Compressed powders (tablets)

15. 1. Bulk powder for internal use
• Powders are dispensed in bulk, when accuracy of dosage
is not important. Bulk powder contains several doses of
powder. They are supplied in wide mouthed containers
that permits easy removal of a spoonful of powder. The
non potent substances which are supplied in bulk are
antacids and laxatives etc.

16. 2. Bulk powders for external use
• Bulk powders meant for external use are non potent
substances. These powders are supplied in cardboard, glass or
plastic containers, which are often designed for the specific
method of application. The dusting powders are preferably
supplied in perforated or sifter top containers.
• The container should bear a label indicating that the powder is
meant for external application.

17. • The bulk powders which are commonly used for
external application are as follows:
a) Dusting powders
b) Effervescent powders
c) Insufflations
d) Snuffs
e) Dentifrices

18. Dusting powders
• These are meant for the external application to the skin and are
generally applied in a very fine state of subdivision to avoid local
irritation.
• Hence, dusting powders should be passed through seive no. 80 to
enhance their effectiveness.
 Dusting powders are of 2 types:
 Medical
 Surgical
 Characteristics
• No local irritation
• Flow easily
• Spread uniformly
• Good covering capacity
• Goof adsorptive and absorptivecapacity

19. • Medical dusting powders are used for superficial skin
conditions, whereas surgical dusting powder are used in body
cavities and also on major wounds as a result of burns and
umbilical cords of infants.
• Medical & Surgical dusting powders before use must be
sterilized by dry heat method at 1600 C for 2 hrs.
• In the preparation of dusting powder the talc or kaolin, starch
are used commonly because these are chemically inert.
• But, such ingredients are readily contaminated with
pathogenic bacteria so, these must be sterilized before their
use by dry heat sterilization method.

20. • The dusting powders are dispensed in sifter or
aerosol containers.
• Dusting powders are generally non- toxic but
inhalation of its fine powdered ingredients by
infants may lead to pulmonary inflammation.
So proper care should be taken while handling.
• Use : Antiseptic, Astringent, Absorbent,
Antiperspirant

21. • Insufflations: These are medicated dusting powder
meant for introduction into body cavities such as, nose,
throat, ears & vagina with the help of an apparatus
“Insufflator”.
 Nowadays, the insufflations are available in the form of
pressure aerosols & these aerosols used for potent
drugs.
 Insufflations are used to produce a local effect in the
treatment of ear, nose, throat infection with antibiotics
or to produce a systemic effect from a drug that is
destroyed in the gut.

22. Disadvantages :
• Non uniform dosage
• Particles stick to each other and to wall of the
insufflator

23. • Snuffs: These are finely divided solid dosage form
of medicament which are inhaled into nostrils for
antiseptic, bronchodilator & decongestion action.
Snuffs are dispensed in flat metal boxes or glass
container with hinged lid.
• Dentifrices (tooth powders): These are applied on
tooth surface with help of brush. They contains
suitable detergent or soap, some abrasive substance
& suitable flavoring agents are involved.
Abrasive agents such as calcium sulphate,
calcium carbonate, sodium carbonate &
sodium chloride are use in fine powder.

24. Effervescent powders
• Effervescent granules/ powders/ salts are the forms of medication
for internal use consisting of a powdered or granulated mixture of
citric acid, tartaric acid, or sodium biphosphate, sod. Bicarbonate
• The presence of water the acid and base react to liberate CO2 and
produce effervescence.
• Storage:
• Effervescent powders should be kept in tightly closed containers.
• Advantages:
• It masks the bitter and nauseous taste.
• It promotes gastric secretions.
• It acts as a carminative.
• Minimum moisture

25. • Sugar : as sweetening agents
• Medicaments : therapeutic action it should be
anhydrous and soluble in water.
• Preparation method :
• 1- Wet method
• 2- Dry method

26. Examples of effervescent powders
• Citric acid
• Tartaric acid
• Malic acid
• Fumaric acid
• Adipic acid
• Sodium bicarbonate
• Sodium carbonate
• Potassium bicarbonate
• Potassium carbonate

28. 3. Simple and compound powders for internal use
• In this form of powder, each individual dose is enclosed
in paper.
• The number of ingredient is one i.e. simple powder while
more than one i.e. compound powder.
• The minimum quantity of each powder should not be less
then 100 mg for it can be handled conveniently by patient
& can be weighed accurately.
Simple powder: In simple powder contains only one
ingredient either in crystalline form or amorphous form.
• If powder present in crystalline form then it is reduced to
fine powder, weighed the powder & divided into number
of doses & wrapped as individual dose.

29. • Compound powders: contains two or more than two substances
which are mixed together. Then divided into desired number of
individual doses which are dispensed into each powder paper.
4. Powders Enclosed in cachets
• Cachets are solid dosage form of drug & cachets are also called as
wafer capsules.
• These are moulded from rice paper, which is made by pouring a
mixture of rice flour and water between two hot, polishes, revolving
cylinders. The water evaporates and a sheet of wafer is formed.
• They are quite hard to swallow as such but they are softened by
dipping in water for a few seconds and then placed on the tongue and
swallowed with a draught of water. After swallowing cachet gets
disintegrate and drug is released.

30. 5. Compressed tablets or tablet triturates or
moulded tablets
• These are powders moulded into tablets.
• They are flat, circular disc & usually contains potent drug
which is mixed with lactose, dextrose or some other
diluents.
• The apparatus is made up of stainless steel or plastic. It
consist of upper & lower perforated plates which is having
an exactly the same number of holes as that of number of
pegs in a lower plate.
• The lower plate also have two large pegs which ensure
correct fitting of the plates.
• The moulds are available in several sizes having a capacity
ranging from 30 to 250 mg.
• Generally 50 to 250 tablet triturates can be prepared at a
time from a tablet triturate mould.

31. • The powder with diluents are mixed together & made a
stiff paste with the help of alcohol 60%.
• Then, paste is introduced on upper plate with the help of
spatula & fill all the holes & removes excess.
• This plate is placed over the lower plate. Then little
pressure is applied over the top plate which will force the
plate move downward, leaving the mould tablet on the
projected pegs.
• Then, prepared tablets dried in hot air oven or by keeping
in warm place.