Definition, Advantages and Disadvantages

1. POWDERS
Ms. Chitralekha G. Therkar
Assistant Professor
Dept. of Pharmaceutics,
Siddhivinayak College of Pharmacy, Warora

2. Introduction
 Pharmaceutical powders are solid dosage form of medicament in
which one or more than one drug is dispensed in finely divided state
with or without excipients.
Pharmaceutical powders = Powdered API + Dry powdered excipients
 They can be used for both internal and external routes of
administration based on the use of it.
 They are available in crystalline as well as amorphous form, crystalline
form indicates the regular internal structure with repeating unit
whereas the amorphous form indicates irregular internal structure.
 There is relationship between particle size of powder, dissolution,
absorption and therapeutic effect of drug.
 The particle size of powders is generally ranges from 10000 micron –
0.1 micron.

3. Advantages  It can be used both internally and externally.
 Powdered dosage forms are very convenient for children and elderly
patients as they can be taken easily as such via oral route or by
dispersing in water.
 It is more chemically stable than liquid dosage form.
 It is convenient for the physician to prescribe a specific amount of
powder.
 The Onset of action is faster as compared to tablet and capsules,
because it can easily dissolved in body fluids due to very small
particle size it get dissolve rapidly.
 Easy to carry.
 No liquid solvents or very less solvents are required during
formulations.
 Easy administration to the patient by dissolving in suitable liquids.
 Powders are more economical than other dosage form since they do
not require any special machinery or techniques.

4.  Drugs have bitter taste, nausea and unpleasant odour cannot be
administered in powder form.
 The Deliquescent and hygroscopic drugs cannot be dispensed in the
powdered form so they should be 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.
 The dispensing of powder is time consuming.
Disadvantages

5. Classification The pharmaceutical powders are classified as follows,
1. Bulk powders for Internal use.
2. Bulk powders for External use.
3. Simple powder for internal use.
4. compound powder for internal use.
5. Powders enclosed in cachets and capsules.
6. Compressed powders (tablets).

6. 1. Bulk powders for internal
use
 When the accuracy of dosage form is not required at the time of
administration, they are dispense in the bulk form.
 Bulk powders consists of several doses of powders.
 They are supplied in wide mouth container with a spoon to
permit easy dispensing for patients.
 The non potent substances which are administered in bulk form
are antacids and laxatives.
Eg’s,
1. Compound Rhubarb powders (Gregory’s powder).
2. Rhubarb powder.
3. Light magnesium carbonate.
4. Heavy magnesium carbonate.
5. Ginger powder.

7. 2. Bulk powders for external
use
 Bulk powders for external use are non potent substances.
 These powders are supplied in the cardboards, glass or plastics
containers which are often designed for the specific method of
application.
 They are generally supplied in perforated or sifter top containers.
 The label on the containers must indicate ‘powders for external use’.
 The bulk powders which are commonly used for external applications
are as follows,
1. Dusting powders
2. Insufflations
3. Snuffs
4. Dentifrices

8. Dusting Powders
 These are meant for external application to the skin. It is applied in
very fine state to avoid local irritation.
 These powders are passed through sieve no. 85( 180µm) to get a
fine powder.
There are two types of dusting powders,
• Medical dusting powder
• Surgical dusting powder
Medical dusting powders are mainly used for superficial skin
condition.
Surgical dusting powders are used in body cavities or wound or
umbilical cords of infants. It must be sterilized before use.
 Dusting powders are generally prepared by mixing two or more
ingredients and they contains antiseptic, astringent, antiperspirant,
anti pruritic. These may also applied with powder puff or sterilized
gauze pad.

9. Insufflations  Insufflations are medicated dusting powder meant for introduction
into body cavities like nose, throat, ears and vagina for treating
infections with the help of an instruments called as insufflators.
 It sprays the powder into a stream of finely powder.
 It is available in pressurized aerosols which can be used for potent
drugs.
 Insufflations are used to produce local and systemic effect from the
drugs that get destroyed in the gut.

10.  Snuffs are finely divided solid dosage forms of medicament which are
inhaled into nostrils.
 It contains antiseptics, bronchodilators, decongestants for there local
and systemic effects.
 Snuffs are dispensed in flat metal boxes or glass container containing
lid with extension.
Snuff

11. Dentifrices
 Dentifrices are the dental powders are applied with the help of a
tooth brush for cleaning the surface of the teeth.
 Dental powders contain detergents or soap, abrasives, antiseptics
and coloring and flavoring agents incorporated in a suitable base.
 Base is calcium carbonate. The detergent is in the form of soap and
the abrasive action is provided by finely powdered pumice stone.
 Essential oils are added to provide flavor and freshness to the mouth
as well as antiseptic action.
Eg, Rx Hard soap, in fine powder - 50.0 g
Precipitated calcium carbonate - 935.0 g
Saccharin sodium - 2.0 g
Peppermint oil - 4.0 ml
Cinnamon oil - 2.0 ml
Methyl salicylate - 8.0 ml

12.  In this form of powder, each individual dose is enclosed in the paper
wrap. If the number of ingredient is one, the powder is said to be
simple and if it is consists of more than one powders it is said to be
compound powders.
 The minimum quantity of each powder shouldn’t be less than 100
mg.
 Simple powders contains only one ingredients either in crystalline or
amorphous form. When the powder is in crystal form then it is
reduced into fine powder by using size reduction methods.
 For dispensing of powders, weigh the powder and divide into
number of doses and wrapped as an individual dose.
Eg, Aspirin – 300 mg
 Procedure – powder the aspirin, weigh the required quantity of
aspirin and wrap each powder in individual powder paper.
3. Simple powders

13.  Compound powders contain two or more than two substance which
are mixed together and then divided into desired number of
individual dosed and dispensed into each powder paper.
 Eg,
• Aspirin 300 mg
• Paracetamol 150 mg
• Caffeine 50 mg
 Procedure – Weigh accurately each powder and mix them as per
ascending order of their weight. Weigh 500 mg of the mixed powder
for each powder and wrap each dose individual in powder papers.
4. Compound powders

14. 5. POWDERS IN CACHETS  Cachets are the solid unit dosage form of drugs and are called as
wafer capsules.
 These are molded from rice paper which is made by pouring a
mixture of rice flour and water between two hot polished cylinders
then the water evaporates and a sheet of wafer is formed.
 Cachets are used to enclose nauseous or disagreeable powders which
are available from 0.2 to 1.5 g of powder in it.
 They are quite hard to swallow as such but they are softened by
dipping in water for few seconds and then place on the tongue and
swallowed with a water.
Advantages – 1. Easy to prepare.
2. Disintegrate quickly in stomach.
3. Drugs can be easily dispensed.
4. Large dose of drug can be swallow by using cachets.

15. 1. Wet seal cachets – it is made of two similar convex halves
having flat edges. The weighed quantity of drug is placed in one
half and edges of other half is moistened with water and placed
over first half containing drug. The flat edges of both halves are
pressed together to seal it.
2. Dry seal cachets - it consists of two halves, the upper half and the
lower half. The diameter of the upper half is slightly larger than the
lower half. The powdered drug is filled in lower half and upper half
is fitted over it. The filled cachets are then sealed in machine by
pressing the two halves.
Types of Cachets

16. 6. TABLET
TRITURATE
 These are powders molded into tablets.
 Molded tablets are flat circular disc are usually contains potent drugs
which is mixed with lactose, dextrose or any other diluents.

17. Preparation of powders The powder is prepared in following steps,
1. Reduction of particle size of all ingredients
2. Sieving
3. Weighing of each ingredient
4. Mixing
5. Packaging

18. 1. Reduction of particle
size of all ingredients
The reduction in particle size is done following methods,
1. Grinding – firstly all the particles are individually get
grinded by grinder or mortar and pestle to reduce their size
from coarse to fine.
2. Sifting – firstly the whole powder is allowed to get sifted
from fine sieve. Then the coarse powders retained over the
sieve is again triturated and repeated the sieving procedure to
get fine particles.
2. Sieving Sieving is done to separate the particles of different sizes from
each other to avoid the irregular contents of powder dosage
form. There are different no. of sieves available varying from
finest to coarse.
Egs, Sieve No. – 100, 80, 60, 40, 20 etc.

19. 3. Weighing of each
ingredient
First of all, the material to be used in the formulation are selected.
If any hygroscopic material is present in the formulation it is then
allowed to dry completely.
After each of the content of powder formulation taken separately
and put on the left side of weighing balance.
The required quantity is then take from main container to butter
paper and weighed the required quantity.
Put the weighed material on the right side of weighing balance.

20.  The aim of mixing is to obtain a homogeneous association of several
solid products.
 Factors influencing the mixing of powders are nature of surface,
density, particle size, particle shape and proportion of materials.
 If these factors are not under control, segregation can occur and the
types of segregation includes percolation and densification.
Methods of Powder Mixing
1. Mechanical Mixing
2. Hand Mixing - a. Spatulation (Spatula + Tile)
b. Trituration (Mortar + Pestle)
c. Tumbling (Wide mouth closed container)
3. Geometric dilution - Entire quantity of potent drug + n volumes of
the diluents + (2n volume) of the diluents + (4n volume) of the diluents
repeated until all the diluents are used.
4. MIXING OF
POWDERS

21. 5. Powder
packaging
 The paper wrapping is divided powders are supplied or dispensed by
wrapping in suitable paper (glazed).
 The paper used for packing of should have following properties,
1. It should fold easily.
2. It should protect the powders without cracking at the fold.
3. It should impermeable to atmospheric condition.
4. It should be water repellant.
5. It should be light weight and elegant.
 Powder papers of special grades are available readily in different in
size otherwise pharmacist may cut the sheets in suitable size.
 The shape of the paper should be rectangular and wrapping of
powders may be single or double wrapping.
 If packed in container, the sifter top containers, pressurized
containers, flat metal boxes.

22. Effervescent granules
 Granules have particle size larger than the powder.
 Basically granules are the wet clumps of the powder which are
prepared after moistening the powder.
 This contains sodium bicarbonate and either citric acid, tartaric
acid or sodium biphosphate in addition to the active ingredients.
 On making solution in water, carbon dioxide is released as a result
of the acid base reaction.
 The effervescence from the release of the carbon dioxide serves to
mask the taste of salty or bitter medications.
 The completed product must be dispensed in tightly closed glass
containers to protect it against the humidity of the air.

23. Effervescent powders  The preparative techniques have been reported for effervescent
powders such as a fluidized bed procedure in which the powders
are blended and then suspended in a stream of air in a Wurster
chamber.
 Water is sprayed into the chamber resulting in a slight reaction
and an expansion of the particles to form granules ranging in size
from 10 to 30 mesh.
 This approach apparently offers a number of advantages over the
older techniques. The extent of reaction and particle size are
controlled during the manufacture.
 A drying oven, trays and even grinding devices are not required.
Furthermore, the technique lends itself to a continuous as well as a
batch operation.

24. Special
Problems
1. Volatile Substances - The loss by volatilization may be
prevented or retarded by use of heat-sealed plastic bags or by
double wrapping with a waxed or glassine paper inside of a bond
paper.
2. Eutectic Mixtures
Liquids result from the combination of phenol, camphor, menthol,
thymol, antipyrine, phenacetin, acetanilid, aspirin, salol and
related compounds at ordinary temperatures.
These so called eutectic mixtures may be incorporated into
powders by addition of an inert diluent.
Magnesium carbonate or light magnesium oxide are used
commonly and effective diluents for this purpose, although kaolin,
starch, bentonite and other absorbents have been recommended.

25. 3. Presence of Liquids - In small amounts, liquids may be
incorporated into divided powders. Magnesium carbonate, starch or
lactose may be added to Increase the absorbability of the powders if
necessary. When the liquid is a solvent for a nonvolatile heat-stable
compound, it may be evaporated gently on a water bath. Lactose may be
added during the course of the evaporation to increase the rate of
solvent loss by increasing the surface area.
4. Deliquescent Substances - Substances that become moist because
of affinity for moisture in the air may be prepared as divided powders by
adding inert diluents. Double wrapping is desirable for further
protection. Extremely deliquescent compounds cannot be prepared
satisfactorily as powders.
5. Hygroscopic Powders – substances that take or absorbs the
moisture from the environment are called as Hygroscopic substances.
The powders which are hygroscopic in nature are if placed open in room
temperature they are more prone to collect the moisture present in the
surroundings.

26. Thank You