powders dosage forms

1. 10/21/2021
1
Prepared & presented by
Ms. Nisha S. Mhaske
Lecturer, PRES’s COPD, Chincholi.
Email : nisha.mhaske@pravara.in
Powders

2. Learning objectives
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⚫ Learner will be able to understand
1. What do you means by powder?
2. What are the methods of preparation of powder?
3. How mixing of powders is to be done?
4. Classification of powders
5. What are the different weighing techniques?

3. Content
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⚫ Powders
⚫ Advantages and disadvantages of powders
⚫ Methods of preparation of powders
⚫ Mixing of powders
⚫ Classification of powders
⚫ Dispensing powders involving special problems
⚫ Weighing techniques

4. Powders
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⚫ A pharmaceutical powder is a mixture of finely divided
drug and/or chemicals in dry form.
⚫ Theses are solid dosage form of medicament which are
meant for internal and external use.
⚫ They are available in crystalline or amorphous form.
⚫ The particle size of powder plays an important role in
physical, chemical and biological properties of the dosage
form.
⚫ There is a relationship between particle size of powder and
dissolution, absorption and therapeutic efficacy of drugs.

5. Advantages Vs disadvantages of powders
Advantages Disadvantages
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1. Powders are one of the oldest dosage form and are
used both internally and externally.
2. Powders are more stable than liquid dosage form.
3. It is convenient for the physician to prescribe a
specific amount of powdered-medicament depending
upon the need of the patient.
4. The chances of incompatibility are less as compared
to liquid dosage form.
5. The onset of action of powdered drug is rapid than
solid dosage form eg. Tablets, capsules or pills.
6. Large quantity of powdered drugs can be easily
administered to the patient orally by dissolving or
mixing the powder in a suitable liquid form.
7. For pediatric and geriatric patients is suitable dosage
form.
8. Powders are more economical because these are
prepared extemporaneously without involving any
special machinery and techniques.
9. Powders are more easy to carry than the liquid
dosage forms.
1. Drugs having bitter, nauseous
and unpleasant taste can not be
dispensed in powdered form.
2. Deliquescent and hygroscopic
drugs can not be dispensed in
powder form.
3. Quantity less than 100 mg or
so, can not be weighed
conveniently on dispensing
balance
4. Drugs which get affected by
atmospheric conditions are not
suitable for dispensing in
powder forms.
5. The dispensing of powder is a
time consuming.

6. Method of preparation of powders
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⚫ During powdering, weighing and mixing, there is loss of
powder which can not be avoided.
⚫ Therefore while calculating the quantity of ingredients calculate
for one extra powder than required.
⚫ The dispensing balance are not very sensitive.
⚫ It is difficult to weigh the quantity less than 2 grain or 100 mg on
the dispensing balance.
⚫ Therefore, the quantity less than 2 grain or 100 mg must be
triturated with a suitable diluents such as lactose, so that the
quantities are made weighable on dispensing balance.
⚫ The crystalline substance are powdered separately and then
weigh the required quantity of each ingredient. Mix all the
ingredients in ascending order of their weights and mix
thoroughly to form a homogenous powder.

7. Mixing of powders
1. Spatulation 2. Trituration
3. Geometric
dilution
4. Sifting
5. Tumbling
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8. 1. Spatulation
⚫ Mixing of powder 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:-
1. Small amount of powder
2. Solid substances that liquefy or form
eutectic mixtures, when in close and
prolonged contact with one another since
very little compression or compact results.
⚫ The method is not suitable for large
quantities of powders or for powders
containing one or more potent substances
because homogenous blending may not
occur.
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9. 2. 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 communication.
⚫ Aglass mortar cleans more readily after use.
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10. 3. Geometric dilution
⚫ Method is used when potent substances are to mixed
with a large amount of diluents.
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11. 4. Sifting
⚫ The powders are mixed by passing through
sifters.
⚫ This process results in a light fluffy product & is generally
not acceptable for incorporation of potent drugs in to a
diluent base.
Pharma Vibro Sifter
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12. 5. Tumbling
⚫ Mixing of powders in a large container rotated by an
electric motor.
⚫ These blenders widely employed in industry as large
volume powder mixers.
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13. Packing of powders
13
⚫ 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. The powders
are wrapped in the following manner:-
1. Cut the required number of powder papers in a suitable size i.e. 120 mm X
100 mm.
2. Arrange the papers with their long edges parallel to the front of the bench and
turn up the long edge of each paper to about one seventh of its width.
3. Weigh out the powder and place towards the front of the paper.
4. Carry the front of the paper over to the turned-up edge ,bring the turn-up
down and then fold this edge forward until it covers about two-thirds of the
distance to the near edge of the packet.
5. Turn the edges of the packet under, using the powder folder so that the
overlap is equal at both ends.
6. Firm the creases using a clean flexible spatula but avoid excessive pressure
which would cause caking of enclosed powder.
7. The packets are arranged in pairs, flap to flap and restrained with an elastic
band.
8. The wrapped powders are send in an envelope if the number of powders are
less than six. In case of large quanti1t0y/2,1t/h20e21boxesare preferred.

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15.  Double wrapping:-White glazed paper
gives inadequate
hygroscopic and
protection
deliquescent
to volatile,
substances
unless it is lined with waxed paper. The
lining is cut a few mm smaller each way
than the white glaze paper and it is quite
satisfactory to fold both papers together. In
exceptional cases, each packet may be
wrapped externally in aluminium foil.
 Labelling:-Patient should be instructed that
individual powder should be dispersed in a
little water or placed on the back of the
tongue before swallowing.
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16. Classification of powders
1. Bulk powder
for internal use
2. Bulk powder
for external use
3. Simple &
compound
powder for
internal use
4. Powders
enclosed in
cachets &
capsules
5. Compressed
powders (Tablets)
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17. 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 container that
permits easy removal of a spoonful of powder.
⚫ The non potent substances which are supplied in bulk
are laxatives and antacids etc.
⚫ Eg- Rhubarb powder B.P.C. (Gregory’s powder)
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18. 2. Bulk powder for external use
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⚫ These are non potent substances.
⚫ These are supplied in cardboard, glass or plastic
containers, which are often designed for the specific
method of application.
⚫ Dusting powders are supplied in perforated or sifter top
containers.
⚫ Direction:- “ For External Use Only”
a. Dusting Powders
b. Insufflations
c. Snuffs
d. Dentifrices

19. a. Dusting Powders
⚫ For External use preparation which is applied to the skin
and are applied in a very fine state of sub division to avoid
local irritation.
⚫ Hence dusting powders should be passed through sieve
No.80 to enhance their effectiveness.
Dusting powders are of two types:-
i. Medical
ii. Surgical
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20. Sr. No. Medical Dusting powder Surgical Dusting powder
1 Mainly used for superficial
skin condition.
Are used in body cavities & major
wounds as a result of burns & umbilical
cords of infants.
2 These are must be free from
pathogenic microorganisms.
Surgical powders must be sterilized
before their use.
3 Dusting powders are prepared by mixing 2 or more ingredients, one of
which must be either starch, talc or kaolin.
These must be sterilized by Dry Heat Method (160ºC for 2 hrs) before
their use.
4 Dusting powders are dispensed in sifter-top containers or aerosol
containers.
5 Dusting powders may also be applied with powder puff or sterilized
gauze pad.
6 Dusting powders are generally considered to be non toxic but the
inhalation of its fine powdered ingredients by infants may lead to
pulmonary inflammation.
7 Dusting powders are mainly used for their antiseptic, astringent,
absorbent, antiperspirant and antipruritic action.
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21. Eg-Dispense 50.0 gm of dusting powder
Rx
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50.0 g
25.0 g
20.0 g
5.0 g
Purified talc, sterilised
Starch, in powder
Zinc oxide, in powder
Salicylaic acid. In powder
Make a powder.
Direction- applied on the affected part 2 or 3 times a day.
Method-
 Powder all the ingredients.
 Weigh the required quantity of purified talc, starch, zinc oxide &
salicylic acid.
 Mix them in ascending order of their weight.
 Pass the mixed powder through a sieve no.85
 After sifting again mix lightly.
 Transfer the powder in sifter top containers to protect it from
atmospheric contamination.

22. b. Insufflations
⚫ These are medicated dusting powders meant for introduction into the
body cavities such as nose, throat, ears and vagina with the help of an
apparatus known as, “Insufflator”.
⚫ Some difficulties generally faced while using the insufflators:-
1. It is difficult to obtain a measured quantity of the drugs as a uniform
dose.
2. It gets blocked when it is slightly wet or the powder used is wet.
⚫ Nowadays, insufflations are available in the form of pressure aerosols.
⚫ These are used for administration of potent drugs.
⚫ This method has the advantage of excellent control of dose through
metered valves.
⚫ It also protects the product from external environment.
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23. Uses of insufflations - to produce local effect, as in the
treatment of ear, nose and throat infection with antibiotics.
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24. c. Snuff
⚫ These are finely divided solid
dosage forms of medicament
which are inhaled into nostrils
for its antiseptic, bronchodilator
and decongestion action.
⚫ Snuffs are dispensed in flat metal
boxes with hinged lid.
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25. d. Dentifrices/ tooth powders
⚫ These are applied with the help of a tooth brush for
cleaning the surface of the teeth.
⚫ They contain suitable detergent or soap, some abrasive
substance and a suitable flavor.
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26. 3. Simple & compound powder for internal use
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⚫ In this form of powder, each individual dose is enclosed in paper.
⚫ The number of ingredients may be one is single powder or more than
one is compound powder.
⚫ The minimum quantity of each powder should not be less than100
mg so that it can be handled conveniently by patient and can be
weighed accurately.
While dispensing simple & compound powders, following rules
should be observed:-
1. Weigh the ingredients after calculating for one extra powder.
2. If the quantity of an ingredient is not directly weighable, calculate
for sufficient extra powders to produce directly weighable quantity.
3. In case of potent ingredient, calculate the amount of lactose to be
mixed to make each powder directly weighable.
4. If the powder contains a liquid, the weight of which is unknown,
adjust the mixed material by the addition of lactose, so that each
powder is directly weighable.

27. a. Simple powder
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⚫ A 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 doses.
Eg. Dispensed six powders of Aspirin each powder contains 300 mg of
aspirin
Rx,
Aspirin 300 mg
Make powder.

28. b. Compound powder
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or more than two
⚫ Compound powders contains two
substances which are mixed together.
⚫ Then divided into desired number of individual doses.
⚫ Then dispensed into each powder paper.
Eg Dispense eight powder ofA.P.C each powder contains
500mg ofA.P.C
Rx,
Aspirin
Paracetamol
Caffeine
300 mg
150 mg
50 mg
Make a powder.

29. 4. Powders enclosed in cachets & capsules
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⚫ Cachets are solid dosage form of drug & cachets are also
called as wafer capsules.
⚫ These are molded from rice flour.
⚫ Rice paper prepared from mixture of rice flour with water
enclosed in between two hot, polished, cylinders.
⚫ Then water was evaporates & wafer is formed.
⚫ In the cachets 0.2 to 1.5 gm nauseous or disagreeable drugs
in powder form are enclosed.
⚫ Cachets are quite hard so, before swallowing they dipped
in water for seconds & then placed on the tongue &
swallowed with draught of water.
⚫ After swallowing the cachets gets disintegrate & drug is
released.

30. Advantages of cachets Disadvantages of cachets
Made easily Required soften before use or
swallowing
Disintegrate quickly in stomach Easily damaged
Drug can be easily dispensed Cannot be protect the enclosed drug
from light & moisture.
Large dose of drug can be
swallowed by using cachets
Shell of cachets are fragile so, drug
contents cannot be compressed in
cachets.
They are not suitable for filling the
drug in large scale.
They occupy more space compare
with tablets & capsules solid
dosage form.
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31. ⚫ Cachets are two types:
1. Wet seal cachets
2. Dry seal cachets
1. Wet seal cachets
⚫ Awet seal cachets is made up of two similar convex halves having flat
edges.
⚫ The weighed of powder drug is placed in one half, the edges of other
half are moistened with water & placed exactly over the first half
containing the drug.
⚫ The flat edges of both the halves are pressed together in order to seal it
perfectly.
Wet Seal
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32. 2. Dry seal cachets
⚫ Dry seal cachets consists of two halves, the upper half & lower half.
⚫ The diameter of upper half is slightly larger than lower half.
⚫ The powdered drug is filled in lower half & upper half is fitted over it.
⚫ The filled cachets are then sealed in a machine by pressing the two
halves, removed & packed in boxes.
⚫ B.P
.C includes two cachets sodium aminosalicylate & sodium
aminosalicylate with isoniazid.
Dry Seal
(With dome)
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Dry Seal
(Without dome)

33. ⚫ Packing & storage of cachets
 The cachets are packed in boxes or tins in which
they are placed on their edges or lying flat.
 Direction:- “Immerse in water for a few seconds
and then swallow with a draught of water.”
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34. 5. Compressed powders (Tablets) or Tablet Triturates or
Moulded Tablets
⚫ In that powders moulded into tablets.
⚫ They are flat, circular disc & usually contains potent drug.
⚫ In that potent drugs are mixed with lactose, dextrose or
some other diluents.
⚫ The used apparatus is made up of stainless steel or plastic.
⚫ It consist of upper & lower perforated plates & having the
same numbers of halves.
⚫ The lower plate also have two large pegs which ensure
correct fitting of the plates.
⚫ They 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.
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35. Cont…
⚫ 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.
Tablet Triturate Mould
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36. Dispensing of Powders Involving Special Problems
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1. Volatile Substances
2. Hygroscopic & deliquescent powders
3. Efflorescent powders
4. Eutectic mixture
5. Liquids
6. Explosive substances
7. Potent drugs
8. Granular powders
9. Effervescent granules

37. 1. Volatile Substances:
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⚫ Certain vegetable powder contains volatile oil.
⚫ To prevent the loss of volatile oils, these vegetable drugs
must be powdered lightly in a mortar.
⚫ Also, menthol, camphor & essential oils take place
incorporation in powder.
⚫ Final product pack with double wrapping.

38. 2. Hygroscopic & deliquescent powders
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⚫ Absorb the moisture from atmosphere are called hygroscopic
powders.
⚫ Absorb the moisture from atmosphere & convert into solution
are called deliquescent powders.
Eg. Ammonium chloride, ammonium citrate, pepsin,
phenobarbitone, sodium iodide etc.
⚫ Such substance are usually provide in granular form in order to
exposé less surface area to atmosphere & avoid convert into fine
powder.
⚫ Such powder should be double wrapped.

39. 3. Efflorescent powders
⚫ Some crystalline substance liberates water of
crystallization wholly or partly on exposure to humid
atmosphere.
Eg. citric acid, caffeine, ferrous sulphate etc.
⚫ So, this problem overcome by mixing or incorporate with
inert substance or using anhydrous slat.
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40. 4. Eutectic mixture
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⚫ When two or more substances are mixed together they liquefy due to
the formation of a compound which has a lower melting point than the
individual substances, such substances are called eutectic substances.
Eg. Menthol, thymol, camphor, phenol, salol, aspirin, phenacetin, chloral
hydrate etc.
⚫ These substances can be dispensed by two methods-
i. Dispense as separate set of powders with directions that one set of
each kind shall be taken as a dose.
ii. An equal amount of any of inert absorbent like magnesium
carbonate, light magnesium oxide, kaolin, starch, lactose, calcium
phosphate etc. may be mixed with eutectic substances & then
blended together lightly with a spatula on a sheet of paper.

41. 5. Liquids
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liquid medicaments are also
⚫ In some prescription the
incorporated with powders.
⚫ In that case, if liquid quantity is small, it may be triturated with
equal amount of powder, then the reset of the ingredients are
incorporated in small proportions with continuous stirring.

42. 6. Explosive substances
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⚫ When an oxidizing substance, such as potassium
chlorate is mixed with reducing substance, such as
tannic acid, there are chances of violent explosion which
may lead to serious consequences.

43. 7. Potent drugs
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⚫ The substance having a max. dose of less than 60 mg &
poisonous substances are called potent drugs.
⚫ It should be difficult to weigh on dispensing balance.
⚫ For that, firstly potent drugs incorporated with diluents such as
lactose before weigh.
Eg. Dispense following powder in 5 powder packets
Rx,
Codeine phosphate 10 mg
⚫ In that case, weigh 100 mg of codeine phosphate & 900 mg of lactose
mixed with ascending order with help of spatula.
⚫ Out of 1 gm of triturate, weigh 100 mg of each powder contains 10
mg of codeine phosphate & pack in powder paper.

44. 8. Granular powders
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⚫ Some solid medicaments required to administered in orally in large dose &
its not possible to convert into tablet or capsule because a large number of
them will be required to take single dose.
⚫ And these medicaments are difficult to dispense in powder form because
its bitter, nauseous & unpleasant taste.
⚫ In this case, solid medicaments mix with sweetening, flavoring & coloring
agent with suitable granulating agent to moisten the powder to make
coherent mass.
⚫ Then, pass through sieve no. 10 to make granules & dry in hot air oven at
600C & after drying pass through sieve no. 20 & pack into wide mouth
containers.
Eg. Nowadays, antibiotics like erythromycin, phenoxymethyl penicillin,
ampicillin etc are available in granular powder because they are unstable in
liquid form.

45. 9. Effervescent granules
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⚫ These type of medicament granules are prepared for internal use.
⚫ In that, medicaments mixed with citric acid, tartaric acid & sodium
bicarbonate with sweetening agents also present.
⚫ When contact with water they release of carbon dioxide to mask the
bitter & saline taste of drug.
⚫ Also, carbon dioxide stimulates the flow of gastric juice & helps in
the absorption of medicaments.
 Methods of Preparation of Effervescent Granules
i. Heat Method
ii. Wet Method

46. i. Heat Method
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⚫ make hot on water bath before
Firstly, porcelain dish
transferring the powder.
⚫ Then, transfer the medicament with citric acid & other
ingredients.
⚫ In that stage citric acid liberates the water & produce dump
mass.
⚫
⚫
⚫ Heating stage takes 1 to 5 min.
Then damp mass pass through sieve & dry in hot air oven at
600C.
Then finally packed in air tight container.

47. ii. Wet Method
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⚫ In this method, the ingredients are mixed with alcohol to
produce coherent mass.
⚫ Produced mass pass through sieve no 10 or 8 & dry in hot
air oven at 600 C.
⚫ Then dried granules are again passed through sieve to
break the lumps which may be formed during drying.
⚫ Finally, the prepared granules are packed in air tight
containers.

48. Weighing Techniques
⚫ Weighing is one of the most important step which is needed in almost
all types of pharmaceutical operations.
⚫ Pharmacist have thorough knowledge of principle, care and use of
balance.
⚫ Dispensing balance consists of simple light but rigid, equal armed
horizontal beam with central and terminal knife edges of steel which
work in agate or steel bearing.
⚫ Two pans are suspended from the terminal knife edges.
⚫ One of pans which is made of glass is used for placing in the material
for weighing. The other pan is made of metal and is used for keeping
the weights on it.
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49. ⚫ The following techniques should be followed while
weighing the materials:-
1. Place the balance in a convenient position for use. The
are should be well-lit and free from dust.
2. Adjust the level of the balance.
3. Clean the balance and pans with a dry duster before
use.
4. Place a clean white sheet of paper under each pan and
replace it frequently to protect the balance from
corrosion.
5. Place the required weights on the left hand pan with
the help of forceps so that swear and grease from the
hands may not make weights inaccurate.
6. Close the drawer of the balance in order to prevent
spillage of the powder on the weights lying in the
drawer.
7. Remove the bottle of medicament from the shelf and
check its label fro the correct ingredient mentioned in
the prescription.
8. Hold the bottle in the left hand with the label in upper
position so that it is visible during weighing.
9. Add or remove the medicament to the right hand pan
with the help of spatula until the pointer returns to the
null point.
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50. 10. When the weighing is completed put the
balance beam again in a fixed position.
11. Transfer the weighed material in a container
or one piece of paper as per requirement.
12. Return the weights to the drawer with
forceps and carefully clean the balance pan
and spatula.
13. Close the bottles and again check its label.
14. Return the bottles to the shelf at a time for
weighing and the same should be replaced
immediately after weighing the material
from it.
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51. Possible errors in weighing
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⚫ Reasons to cause errors:-
1. The balance is not properly leveled.
2. The rest point of the balance is not correct.
3. The two pans of the balance are of unequal
weights.
4. The surface of the pans are rough.
5. The material is weighed directly on the pan.
6. The material is weighed even though the pans
are still oscillating.
7. Weights are handled with hand and not with
forceps.

52. ⚫ Minimum weighable amounts
1. The laboratory experiments have proved that when
dispensing balance is used for weighing, a minimum
weighable quantity should not be less than 2 gr or 100
mg to maintain an error of ± 5.
2. In case of potent drug, diluents are added by geometric
dilution method of mixing.
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53. ⚫ Proper care and usage of
dispensing balance
⚫ Electronic Balance
⚫ Taring the weighing vessels-
reset the balance to zero
⚫ Weighing by difference-
Viscous substances
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54. Marketed solid dosage forms
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Sr. No Powder type Name of the product
1 Powders Oral Rehydration Salt
Acidin
Electrobion
Prequest powder
2 Dusting powders Cibazol dusting powder
Nebasulf dusting powder
Neosprin dusting powder
Mycoderm dusting powder
3 Dentifrice Sensodent-K
Thermoseal
Senolin
4 Granules Protinex
Protinules
Electral
Calcirol
5 Effervescent granules Eno fruit salt
Cetro-soda

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