pharmaceutical powders belongs to solid dosage form their preparation ,classification and dispensing of powders involving special problems

1. POWDERS
Presented by
V.Rajani
Assistant.Professor

2. CONTENTS
• Definition
• Advantages and disadvantages
• Classification
1. Bulk powder for internal use
2.Bulk powder for external use
3. simple and compound powder for internal use
4. powders enclosed in catchets and capsules
5.compressed powders (tablets)
• Mixing of Powders
i. Spatulation
ii. Trituration
iii. Geometric dilutions
iv. Sifting
v. Tumbling
• Dispensing of powders involving special problems
a. hygroscopic powders
b. efflorescent powders
c. effervescent powders
d. eutectic mixtures

3. Introduction
• Definition: A Pharmaceutical powders is a
mixture of finely divided drug and/or
chemicals in a dry form. These are solid
dosage forms of medicament which are meant
for internal or external use.
• They are available in crystalline or amorphous
form.

4. 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
• On set of action is faster as compared to tablet,
capsules .because it is easily in dissolved in body fluids
• Easy to carry
• Easy to administration to the patient orally by
dissolving in suitable liquids.

5. DISADVANTAGES:
• Drugs 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. CLASSIFICATION OF POWDERS
• Bulk powders for internal use
• Bulk powders for external use
• Simple and compound powder for internal use
• Powders enclosed in cachets and capsules
• Compressed powders(tablets)

7. 1. BULK POWDERS FOR INTERNAL USE
i. Powders are dispensed in bulk when accuracy of dosage is
not important .
ii. They are supplied in wide mouthed container with spoon
Example:
Compound Rhubarb powder B.P.C(Gregory's powder)
RX
1.Rhubarb powder -250 g
2.Light magnesium carbonate -325 g
3. Heavy magnesium carbonate- 325 g
4.Ginger in powder -100g
• Direction : 0.5 g to 5 gm to be taken twice a day

8. 2.BULK POWDERS FOR EXTERNAL USE
A. Dusting powders
B. Insufflations
C. Snuffs
D. Dentifrices
The label must indicate powders for external use
A. DUSTING POWDERS :
• These are meant for external application to the skin.
• It is fine state to avoid local irritation .
• These powders passed through sieve no 80 to get a fine powder.
• They are two types
i. Medical dusting powder
ii. Surgical dusting powder

9. • 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 used.(Hot air oven, at 160o C for 2 hrs)
• Dusting powders are generally prepared by mixing two
or more ingredients (Talc/ Kaolin).
• DUSTING POWDERS contains antiseptic , astringent ,
antiperspirant ,antipruritic.
• These may also applied with powder puff or sterilized
gauze pad.

10. Example of Dusting powder
Rx
1.Purified talc, sterilized -50.0 g
2.Starch, in powder -25.0 g
3.Zinc oxide, in powder -20.0 g
4.Salicylic acid, in powder- 5.0 g
Direction: Applied on the affected part two or
three times a day.

11. B.INSUFFLATION :
• These are medicated
dusting powder meant for
application into body
cavities like nose, throat ,
ear infection with the
help of insufflators .
• It sprays the powder into
a stream of finely powder
• It is available in
pressurized aerosol
container

12. C.SNUFFS :
• These are finely divided
solid dosage forms of
medicament which are
inhaled into nostrils .
• It contains antiseptics,
bronchodilators
,decongestant
• Snuffs are dispensed in
flat metal boxes with
hinged lid

13. D.DENTIFRICES :( TOOTH POWDER )
• Dental powders are applied with the help of a tooth
brush for cleaning the surface of the teeth.
• Dental powders contain detergents, abrasives,
antiseptics and colouring and flavouring agents
incorporated in a suitable base.
• The abrasive agents such as calcium sulphate,
magnesium carbonate, sodium carbonate and sodium
chloride are used in fine powder.
• Essential oils are added to provide flavour and
freshness to the mouth as well as antiseptic action.

14. Example of Dentifrices NFXI
Rx
1.Hard soap, in fine powder -50.0 g
2.Precipitated calcium carbonate -935.0 g
3. Saccharin sodium -2.0 g
4.Peppermint oil -4.0 ml
5. Cinnamon oil -2.0 ml
6.Methyl salicylate -8.0 ml
Direction: To be applied on the surface of the teeth
with the help of tooth brush.

15. 3.SIMPLE AND COMPOUND POWDERS FOR INTERNAL USE :
• In this form of powder each individual dose is enclosed in
paper .
• The number of ingredients may be one ( simple ) or more
than one ( compound ) The minimum quantity of each
powder shouldn’t less than 100 mg.
Simple powders: contains only one ingredients either in
crystalline or amorphous form.
• When the powder is in crystal form it is reduced into fine
powder .
• Weigh the powder and divided into number of doses and
wrapped as individual doses .

16. Compound powders:
• These 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.
• E.g. Powders of A.P.C
i. Aspirin -300 mg
ii. Paracetamol -150 mg
iii. Caffeine -50 mg

17. 4.POWDERS ENCLOSED IN CACHETS : (WAFER CAPSULE ) :
• Cachets are the solid unit dosage form of drugs . These
are molded from rice paper .
• which is made by pouring a mixture of rice flour and
water between two hot polished cylinders .
• The water evaporates and a sheet of wafer is formed.
• Cachets are used to enclose nauseous or disagreeable
powders are available from 0.2 to 1.5 g of powder .
• 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

18. • Disadvantage of Catchets:
• It must be softened before swallowing .
• They cannot protect the drug against light
moisture
• The shell of cachets are fragile
TYPES OF CACHETS :
a. Wet seal cachets
b. Dry seal cachets

19. a.Wet seal cachets :
• A wet seal cachets is made up of two similar convex
halves having flat edges .
• The weighed quantity of powdered drug is placed in
one half , the edges of the other half moistened with
water and place exactly over the first half containing
drug .
• The flat edges of both the halves are pressed together
to seal it
DIRECTION : IMMERSE IN WATER FOR FEW SECONDS
AND THEN SWALLOW WITH DRAUGHT OF WATER

20. • DRY SEAL CACHETS :It consists of two halves ,
the upper half and the Lower half .
• diameter of the upper half is slightly larger
than the lower half .
• 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. Eg. Sodium
aminosalicylate

21. 5.TABLET TRITURATES (Moulded Tablets) or compressed powders :
• These are powdered moulded into tablets .
• Moulded tablets are flat circular disc are usually contains potent
drugs which is mixed with lactose , dextrose ( diluents ).
⚫ The used apparatus is madeupof stainlesssteel orplastic.
⚫ Itconsistof upper & lowerperforated plates & having the
same numbersof halves.
⚫ The lowerplatealso havetwo large pegswhich ensurecorrect
fitting of the plates.
⚫ Theyareavailable in several sizes having acapacityranging
from 30 to 250 mg.
⚫ Generally 50 to 250 tablet trituratescan be prepared ata time
from a tablettriturate mould

22. ⚫ The powder with diluents are
mixed together& madeastiff
pastewith the helpof alcohol
60%.
⚫ Then, paste is introduced on
upper platewith the helpof
spatula & fill all the holes &
removesexcess.
⚫ Thisplate is placed overthe lower
plate.
⚫ Then littlepressure isapplied over
the top plate which will force the
plate movedownward, leaving the
mould tableton theprojected
pegs.
⚫ Then, prepared tabletsdried in
hotair ovenor by keeping in warm
place.

23. Preparation of powders
1. Reduction of particle size of all ingredients
2. Sieving.
3. Weighing of each ingredient.
4. Mixing.
5. Packaging.

24. MIXING OF POWDERS
• The aim of mixing is to obtain a homogeneous
association of several solid products.
• Factors influencing the mixing of powders-
nature of surface, density, particle size, particle
shape, particle charge and proportion of
materials.
• If these factors are not under control, segregation
(demixing) can occur.
• Types of segregation include percolation,
trajectory and densification.

25. • Methods of Powder Mixing
1) Mechanical Mixing
2) Hand Mixing
• Mixing of Powders
i. Spatulation
ii. Trituration
iii. Geometric dilutions
iv. Sifting
v. Tumbling
A. Spatulation (spatula + tile): In this method, mixing of powders is done by the movement of spatula
throught the powders on a sheet of paper or on a porcelian tile .
This method is not suitable for large quantities of powders or powders containing one or more
potent substances because homogenous blending may not occur
B. Trituration (mortar + pestle) : It is used both to reduce particle size and mix powders . If particle size
reduction is desired along with mixing of powders, a porcelian mortar with a rough inner surface
is preferred to a glass mortar with a smooth working surface.

26. C. Geometric dilution: The method is used when potent
substance are to mixed with a large amount of diluent.
• Entire quantity of potent drug (x volume) + (x volume) of the
diluents + (2x volume) of the diluents + (4x volume) of the
diluents………repeated until all the diluents are used.
• For example , if 100 mg of potent drug is requried to be mixed with
900 mg of lactose, then according to geometric dilution, the
following procedure should be followed :-
100 mg of potent drug + 100mg of lactose=200 mg of mixture
200 mg of potent drug + 200mg of lactose=400 mg of mixture
400 mg of potent drug + 400mg of lactose=800 mg of mixture
800 mg of potent drug + remaining portion of lactose=1000 mg of
mixture

27. D. Sifting : The powders are mixed by passing
through sifters .this process result in a light fluffy
product and is generally not acceptable for
incorporation of potent drugs into a diluent base.
E. Tumbling : tumbling is the process of mixing
powders in a large container rotated by an
electric motor. These blensers are widely
employed in industry as large volume powder
mixers.

28. packaging of Powder
• PAPER WRAPPING :
• Divided powders are supplied or dispensed by
wrapping in suitable paper(glazed).
• paper used for packing of powder should have
following properties:
• It should fold easily.
• should protect the powders without cracking at the
fold.
• It should impermeable to atmospheric condition.
• It should be water repellant.
• It should be light weight and elegant.

29. • Powder papers (glazed) 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.
• The wrapping of powders may be single or
double wrapping.
• Also Packed in sifter top containers,
pressurized containers, flat metal boxes.

30. • Dispensing of powders involving special
problems
a. hygroscopic powders
b. efflorescent powders
c. effervescent powders
d. eutectic mixtures

31. a. Hygroscopic powders
- Absorb the moisture from atmosphere are called
hygroscopic powders.
- Absorb the moisture from atmosphere & convert into solution are
called deliquescent powders.
- E.g. ammonium chloride, ammonium citrate,
pepsin, phenobarbitone, sodium iodideetc.
- Such substance are usually provide in granular form in order to exposé
less surface area to atmosphere & avoid convert into fine powder.
- Such powdershould bedoublewrapped.

32. b. Efflorescent powders
- Some crystalline substance liberates water
of crystation whollyor partly on exposure to
humid atmosphere.
- e.g. citricacid, caffeine, ferrous sulphateetc.
- So this problem overcome by mixing or
incorporate with inert substance or usiing
anhydrous salt.

33. c. Effervescent powders
• Effervescent powders contain materials which react in
presence of water evolving carbon dioxide
• This class of preparations can be supplied either by
compounding the ingredients as granules or dispensed
in the form of salts.
• For evolution of the gas two constituents are
essential, a soluble carbonate such as sodium
bicarbonate and an organic acid such as citric or
tartaric acid
• The preparation can be supplied either as a bulk
powder or distributed in individual powders.

34. d. Eutectic mixtures
• Eutectic mixtures are defined as mixtures of low melting point ingredients
which on mixing together turn to liquid form due to depression in melting
point of the mixture below room temperature.
• They are mixtures of substances, that liquefy when mixed, rubbed or
triturated together.
• The melting points of many eutectic mixtures are below room
temperature.
• Examples of the substances which tend to liquefy on mixing are camphor,
thymol, menthol, salol.
• Any two of these drugs turn to liquid when mixed.
• This problem during formulation of powders of such material can be
solved by using inert adsorbent such as starch, talc, lactose to prevent
dampness of the powder and dispensing the components of the eutectic
mixture separately.