Pharmaceutical powders, B.pharm, Pharm.D

Spatulation
Trituration
Geometric dilution
Sifting
Tumbling
Bulk powder for internal use
Bulk powder for external use
Simple and compound powder for internal use
Powders enclosed in cachets and capsules
Compressed powders (tablets)
Dusting powders
Insufflations
Snuffs
Dentifrices

1. POWDERS
Ms. Fayeja M Zankhwala

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. •Chances of incompatibility are less as
compared to liquid dosage forms.
•Powders are more economical as compared to
other solid dosage form

5. 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.

6. 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.

7. 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

8. 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

9. ✓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.

10. ✓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.

11. ✓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.

12. •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.

13. ✓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.

14. 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.

15. 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)

16. 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.

17. 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.

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

19. 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 sieve no. 80 to enhance their
effectiveness.

20. ❑Dusting powders are of 2 types:
❖Medical
❖Surgical
❑Characteristics
•No local irritation
•Flow easily
•Spread uniformly
•Good covering capacity
•Goof adsorptive and absorptivecapacity

21. •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 160
0
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.

22. •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

23. •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.

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

25. •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.

26. 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.
.

27. ❑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
❑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.

28. •Powders Enclosed in cachets
•Cachets are solid dosage form of drug & cachets
are also called as wafer capsules.
•It holds 0.2-1.5 gm powder.
•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.

29. •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. •Advantages of cachets:
•Easily made
•Drugs can be easily dispensed
•Disintegrates quickly in the stomach
•Disadvantages of cachets:
•Must be softened before swallowing
•Easily damaged
•Drugs Cannot protect light or moisture
•Not suitable at large scale

31. 5.Compressed tablets
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.

32. •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.

33. •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.

34. 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
CO
2 and produce effervescence.
•Advantages:
•It masks the bitter and nauseous taste.
•It promotes gastric secretions.
•It acts as a carminative.
•Minimum moisture

35. •Storage: Effervescent powders should be kept
in tightly closed containers.
•Sugar : as sweetening agents
•Medicaments : therapeutic action it should be
anhydrous and soluble in water.
•Preparation method :
•1- Wet method
•2- Dry method / Heat method

36. •1- Wet Method
•Mixed ingredients with non-aqueous liquid to
prepare a mass
•Pass through a sieve no 8
•Dried in oven at below 60 °C
•Dried granules again passed through the sieve to
break the lumps which may be formed during
sieving
•Packed air tight container and labelled it.

37. •2. Dry Method / Heat Method
•Take a large porcelain / SS evaporating dish.
•Place over the boiling water bath.
•Dish must be sufficient hot before transferring the
powder into it, to ensure liberation of water of the
crystallisation from the citric acid.
•If the heating of dish delayed, the powder which added
to it, will heat up slowly and liberated water of
crystallisation will be go on evaporation
simultaneously.
•As results sufficient water will not be available to make
a coherent mass.

38. •Water is needed for granulation process and
that provided from two sources:
I.Crystallisation of citric acid, CA contains 1
molecule of water which is liberate during
heat.
II.Water produce from the reactions of CA and
TA and sod. Bicarbonate.

39. •Heating stage take 1-5 min.
•Dump mass pass through sieve and dried it in
oven below 60 °C.
•Packed in air tight container.

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

41. Efflorescent powders
•Some Efflorescent powders Crystalline in nature.
•Such as caffeine, citric acid, codeine, atropine.
•This type of pharmaceutical Powder would
become sticky if exposed to a low-humidity
environment as the water gets liberated from the
Powder.
• It can be overcome by using anhydrous salt or an
inert substance may be mixed with efflorescent
substances before incorporating with other
ingredients.