This document provides information about powders and granules. It defines powders as solid materials in a finely divided state that can be used orally or externally. Powders are classified based on use as bulk powders for internal or external use, or divided doses. Granules are agglomerated powders made into larger, free-flowing particles. The document describes the mixing, preparation, advantages, disadvantages, storage, packaging, and uses of powders and granules. Common pharmaceutical applications include antacids, analgesics, and skin protectants.

2. Groupname:
MEDSPREDATORS
Topic: Powders and
Granules

3. TOPIC CONTENTS:
Powder:
a)Introduction
b) Classification
c) Mixing of powders
d)Method of preparation
e)Advantages and disadvantages
f)Shelf life and storage
g)Containers
h)Packaging
i)Labeling
j)Pharmaceutical uses

4. Introduction:
Defination:
Powders may be defined as a
solid material in a finely divided state.
A powdered drug on its own can be a
dosage form for taking orally (called
simple powder) when they are usually
mixed with water first, or for external
application as a dusting powder.

5. Classification of Powders:
(a)Classification on the basis of use:
1)Bulk powder for internal use
2)Bulk powder for external use
3)Divided or unit doses powder

6. 1).Bulk powder for internal use
• They are mixture of finely divided drugs and
or chemicals in a dry form that may be
intended for internal use (oral powders)
• Types:
• a)Oral powder
• b)Powder spray
• c)Dry powder inhalers
• d)Effervescent powders

7. 2).Bulk powder for external use
• They are mixtures of finely divided drugs
and/ or chemicals in a dry form that may be
intended for external use available in
multiple doses (dusting powder)
• Types:
• a)Dusting powders
• b)Insufflations
• c)Dentifrices

8. 3)Divided powder
• Divided powder are similar formulation to
bulk powder but individual doses are
separately wrapped.
• Types
• a)Douche powders
• b)Powder for injection
• c)Effervescent powders

9. Size classification of powders

10. Mixing of powders
• Ingredients of powder should be mixed thoroughly
using the technique of doubling-up to insure an
even distribution(some times called geometric
dilution).
• This process involves starting with ingredient which
has smallest bulk.
• The other ingredients are added progressively in
approximately equal parts by volume.
• In this way the amount in the mortar is
approximately doubled at each addition.

11. Mixing of powders
• Mixing in b/w additions continues until all
the ingredients are incorporated.The powder
can then be packed.

12. Method of preparation
• 1- Reduction of particle size of all ingredients
to the same range to prevent stratification.
• 2- Sieving.
• 3- Weighing of each ingredient.
• 4- Mixing.
• 5- Packaging.

14. (a)General method for
preparation of bulk powders:
(1)Weigh the powder present in smallest
volume(powder A) and placed in mortar.
(2)Weigh the powder present in the next
largest volume(powder B) and placed on
labeled weighing paper.
(3)Add approximately same amount of powder
B as powder A in the mortar.

15. (a)General method for preparation of
bulk powders:
• Mix well with pestle.
• Continue adding amount of powder B that is
approximately the same as that in the mortar
and mix with the pestle,i.e doubling the
amount of powder in the mortar at each
addition.

16. (b)General method for
preparation of divided powders:
1)The minimum weight of individually wrapped
powder is 120mg.Dilution of drug with a
diluent usually lactose is often necessary to
produce this weight.
2)Usually tablets or capsules may be used to
prepare oral powders . This involves either
crushing the tablets in a mortar and pestle,or
emptying the contents of the capsule and
adding a suitable diluent.

17. (b)General method for
preparation of divided powders:
3)Lactose is most commonly used diluent
because it is colourless,odourless,soluble,is
generally harmless and has good flow
properties.
4)Some patients may be unable to tolerate
lactose and a suitable inert alternative
diluent,for instance light kaolin,would then be
used.

18. Powder calculations:
• While dealing powders calculations
–Always calculate for at least 1 extra
powder to compensate loss of powder
during manipulations.
– If amount of active ingredient is less than
minimum weighable qty than dilutions
(triturations) are to be made.
–Min. weighable qty is diluted over several
time to obtain req. dose.

19. Powder calculations:
A. Doubling up method
B. Calculations involving powder volumes

20. Example:
• E.g.
• Rx
• Hyoscine HBr 300 mcg
• mitte 4 powders
• one to given 30minutes before journey
• (Remember: minimum powder weight for divided powder =
120mg)
•
• Calculate for 5 doses
• Active req. = ?
• Diluent (lactose) req. = ?

21. Powder calculations:
• Step-1
• Hyoscine HBr =100mg
• Diluent =900mg
• Step-2
• Triturate A =100mg
• Diluent =900mg
• Step-3
• Triturate B =?
• Diluent =?

22. Folding of paper
It involves following steps:
(A)The long edge away from the dispenser should
be turned over to about one-7th of the paper
width.
(B)The powder should be weighed accurately and
placed on the paper towards the folded edge of
the centre of the paper.
(C)The unfolded long edge should then be brought
over the powder to meet the crease of the folded
edge and the flap closed over it.

23. Folding of paper
(D)The folded edge should then be folded
over(towards the dispenser)so that it covers about
half the powder packet.
(E)The short edges of the powder packet should be
folded over. using a powder cradle if available,so
that flaps are of equal lengths and the folded
powder fits neatly into a box a jar.Before making
these folds ensure that there is no powder in the
ends to be folded,otherwise it may fall out and be
lost.

24. Folding of paper

25. Advantages of powders:
• Good chemical stability compared with fluids
• useful for bulky drugs with large dose, e.g.
indigestion powder.
• Easy to swallow even in large bulk, especially if
mixed with drink food (useful for stomach- tube
feeding)
• The smaller particle size of powders causes
more rapid dissolution in body fluids, increases
drug bioavailability, and decreases gastric
irritation compared with tablets.

26. Advantages of powders:
.Faster dissolution rate/Bioavailability
Increase S.A ------- increase dissolution
Rapid onset of action
.Can be taken orally by some patients who are
unable to swallow other solid dosage forms
such as capsules and tablets.

27. Disadvantages of
powders:
• Not suitable for drugs unstable in
atmospheric conditions
• Not suitable for bitter, nauseating, deliquesnt
and corrosive drugs.
• Inaccuracy of dose in case of bulk powder
• Inconvenient to carry.

28. Shelf life and storage of internal
powders
(1)Shelf life of internal powders is 2-4 weeks.
(2)Proprietary powders often have a longer
shelf life because of protective packaging.
(3)Storage for these powders should be
moisture proof and airtight.

29. Shelf life and storage of external
powders
• Shelf life of external powders is 4 weeks.
• Dry powders should remain stable for long
period of time if packaged and protected
from atmosphere.
• Store in a cool and dry place.

30. Containers for internal powders
• Extemporaneously prepared individualy
wrapped powders are often dispensed in a
paperboard box.
• It is preferable to use a screw-top glass or
plastic container which provides an air tight
seal and protection against moisture.
• Bulk powders are packed in an airtight glass
or plastic jar.

31. Containers for internal powders

32. Containers for external powders
• Powders for external use may be packed in
glass,metal or plastic containers with a sifter-
type cap. Some are also available
commercially in pressurized
containers,containing other excipients such
as propellant and lubricants.

33. Containers for external powders

34. Labels and advice for internal
powders
• Powders are usually mixed with water or
another suitable liquid before
taking,depending upon their solubility.
• Powders for babies can be placed directly
into mouth followed by a drink to wash down
the powder.
• Bulk powders should be shaken and
measured carefully before dissolving in a
little water and taking.

35. Labels and advice for internal
powders:

36. Labels and advice for external
powders
• For external use only.
• Store in cool ,dry place.

37. Labels and advice for external
powders:

38. Uses of powders:
• Powders are used as counter-irritant e.g
/camphor starch dusting powder.
• Rhubarb powder is used in dyspepsia.
• Chlorhexidine dusting powder is used as
antimicrobial.
• Dover’s powder( ipecacuanha and opium) is
used as antipyretic.
• Magnesium trisilicate powder is used as
antacid and anti-flatulent.

39. Uses of powders:
• Powders are also used as antiseptics.

40. Uses of powders:
• Ibuprofen powder is used to treat juvenile
arthritis.
• Rumford is used as aluminium free baking
powder.

41. Uses of powders:
• Powders are also used in cosmetics as face
powders.

42. Uses of powders:
• Prickly heat powders are used to relief skin
burn.

43. Uses of powders:
• Baby powders are used to protect skin and
nappy rashes.

44. TOPIC CONTENTS:
• Granules:
• a)Introduction
• b) Classification
• c)Method of preparation
• d)Advantages and disadvantages
• e)Shelf life and storage
• f)Containers
• g)Packaging
• h)Labeling
• i)Pharmaceutical uses

45. Introduction
• Granules are powder agglomerated to
produce large free flowing particles.
• Granules are particles ranging in size from
about 4 to 10 mesh.
• They are irregularly shaped but may be
prepared to be spherical.
• Granulation are also used as intermediates in
the preparation of capsule and tablets,since
they flow more smoothly and predictably
than do small powder particles.

46. Granules

47. Why we prepare granules when we
have powders?
• To avoid powder segregation.
• To enhance the flow of powder.
• Granules have higher porosity than powders.
• To improve the compressibility of powders.
• Materials, which are slightly hygroscope, may
adhere & form a cake if stored as a powder.

48. Classification
Granules are classified into following
categories:
1)Effervescent granules.
2)Coated granules.
3)Gastro-resistant granules.
4)Modified release granules.

49. 1:Effervescent granules
• Effervescent granules are uncoated granules
generally containing acid substances and
carbonates or hydrogen carbonates which
react rapidly in the presence of water to
release carbon dioxide.
• They are intended to be dissolved or
dispersed in water before administration.

50. Effervescent granules

51. 2:Coated granules
• Coated granules are usually multi-dose
preparations consist of granules coated with
one or more layers of mixtures of various
excipients.
• The substances used as coatings are usually
applied as solution or suspension in
conditions in which evaporation of the
vehicle occur.

52. Coated granules

53. 3:Gastroresistant granules
• These are delayed release granules that are
intended to resist the gastric fluid and to
release the active substance in intestinal fluid
• These properties are achieved by covering
the granules with the gastro-resistant
material or by other suitable means.

54. Gastro-resistant granules

55. 4:Modified release granules
• They are coated or uncoated granules which
contain special excipients or which are
prepared by special procedure are both ,
designed to modified the rate , the place or
the time at which the active substance or
substances are released.
• Modified release granules include prolonged
release granules and delayed release
granules.

56. Modified release granules

57. Advantages and Disadvantages of
granules
Advantages
• Granules are more flowable
compared to powder.
• Segregation of the
constituents of the powder
mixture could be avoided by
granulation.
• Granules are more stable
against humidity and
atmosphere.
• Granules are more easily
wetted by liquids than light
and fluffy powders.
Disadvantages
.The masking of bitter tastes
may be a problem with this type
of preparation.
• Granules are not a good
method of administering
potent drug with low dose.
• Instability in presence of
moisture.
• Problems in packaging and
storage.

58. Methods of preparation
Granules are generally prepared by two
methods.
1)Wet method
2)Dry method

59. Wet method:
• wet method is to moisten the powder or
powder mixture and then pass the resulting
paste through a screen of the mesh size to
produce the desired size of granules.
• The granules are placed on drying trays and
are dried by air or under heat.
• The granules are periodically moved about
on the drying trays to prevent adhesion into a
large mass.

60. Wet method:
• Another type of wet method is fluid bed
processing, in which particles are placed in a
conical piece of equipment and are
vigorously dispersed and suspended while a
liquid excipient is sprayed on the particles
and the product dried, forming granules or
pellets of defined particle size.

61. Fluid bed processing:

62. Dry method:
• Dry granulation is performed by two ways.
• a) Roll compactor
• b) Slugging

63. a) Roll compactor:
• Dry powder is passed through a roll compactor and
then through a granulating machine.
• A roll compactor, also called a roll press or roller
compactor, processes a fine powder into dense
sheets or forms by forcing it through two
mechanically rotating metal rolls running counter to
each other .
• The surface of the compacting rolls may be smooth
or may have pocket indentations or corrugations
that allow compaction of different forms and
textures.

64. a) Roll compactor:
• The compacted powder is granulated to
uniform particle size in a mechanical
granulator. Powder compactors are generally
combined in sequence in integrated
compactor–granulation systems.

65. a) Roll compactor:

66. b)Slugging:
• Slugging, is the compression of a powder or
powder mixture into large tablets or slugs on
a compressing machine under 8,000 to
12,000 lb of pressure, depending on the
physical characteristics of the powder.
• The slugs are generally flat-faced and are
about 2.5 cm (1 inch) in diameter.

67. b)Slugging:
• The slugs are granulated into the desired
particle size, generally for use in the
production of tablets. The dry process often
results in the production of fines, that is,
powder that has not agglomerated into
granules. These fines are separated,
collected, and reprocessed.

68. Preparation of effervescent
granules:
• These granules are prepared by two
methods:
• A)Fusion method
• b)Wet method

69. A)Fusion method:
• In the fusion method, the one molecule of water
present in each molecule of citric acid acts as
the binding agent for the powder mixture.
• Before mixing the powders, the citric acid
crystals are powdered and then mixed with the
other powders of the same sieve size to ensure
uniformity of the mixture.
• The sieves and the mixing equipment should be
made of stainless steel or other material
resistant to the effect of the acids.

70. A)Fusion method:
• The mixing of the powders is performed as rapidly as is
practical, preferably in an environment of low humidity to
avoid absorption of moisture and a premature chemical
reaction.
• After mixing, the powder is placed on a suitable dish in an
oven at 34°C to 40°C.
• During the heating process, an acidresistant spatula is
used to turn the powder.
• The heat releases the water of crystallization from the
citric acid, which, in turn, dissolves a portion of the
powder mixture, setting the chemical reaction and
consequently releasing some carbon dioxide.

71. A)Fusion method:
• This causes the softened mass of powder to become
somewhat spongy, and when it has reached the
proper consistency (as bread dough), it is removed
from the oven and rubbed through a sieve to produce
granules of the desired size.
• A No. 4 sieve produces large granules, a No. 8 sieve
prepares medium size granules, and a No. 10 sieve
prepares small granules.
• The granules are dried at a temperature not
exceeding 54°C and are immediately placed in
containers and tightly sealed.

72. B)Wet method:
• The wet method differs from the fusion method
in that the source of binding agent is not the
water of crystallization from the citric acid but
the water added to alcohol as the moistening
agent, forming the pliable mass for granulation.
• In this method, all of the powders may be
anhydrous as long as water is added to the
moistening liquid.
• Just enough liquid is added (in portions) to
prepare a mass of proper consistency; then the
granules are prepared and dried.

73. Example:
• Sodium citrate and tartrate B.P.
• Ingredients Quantity
1) Sodium bicarbonate 510gm
2) Tartaric acid 270gm
3) Citric acid 180gm
4) Sucrose 150gm

74. Shelf life and storage:
• Shelf life of granules is 2-3 weeks.
• Granules should be stored in airtight
containers.
• Granules should be placed at cool and dry
place.

75. Container
• Granules should be kept in air tight container.

76. Container:

77. Label and advice
• Dissolve or mix with water before taking.
• A normal dose is 1-5 g of the powder taken in
liquid, when required.
• Antacids are usually taken b/w meals and at
bedtime.

78. Label and advice:

79. pharmaceutical uses:
• Effervescent granules are used as an antacid.

80. pharmaceutical uses:
• Methylcellulose granules are used as a
laxative.

81. Uses of granules:
• Granules are also used in fertilizer industry.

82. Uses of granules:
• Granules are used for instant preparation of
solutions and suspensions.

83. Uses of granules:
• Lactinex granules are use in uncomplicated
diarrhea.

84. Uses of granules:
• Granules are also used as animal foods.

85. Powders Granules
• Comparatively poor flow properties • Flow well compared to tablets, good
choice for compressing tabs
• Relatively less stable (physically and
Chemically) due to inc. S.A & Atm. Effect
• Has less surface area, more stable to atm.
effect
• More likely to hardening / cake formation
on long storage
• Less likely
• For some powders, drugs float on the
surface, difficult to make solution
• More easily wetted by the solvents, good
choice reconstitution liquids
• Relatively poor compressibility • Good compressibility
• Chances of non uniform dosing are more • Relatively more uniformity of contents in
case of granules
• More dust due to small particle size • Generate less dust on handling
• Comparatively less appealing • Have a more elegant appearance
• Relatively simple method of
processing/formulation
• It involves more processing, exposure to
heat and contact with solvents
Powders VS Granules