Powders 6

Question 1

What is granulation

Answer 1

process in which mixture of primary powder particle form larger, homogeneous multi particle entities called granules

Question 2

why do we granulate

Answer 2

to improve

powder flow
compaction

to prevent

segregation

Question 3

Describe the process of wet granulation

Answer 3

api and excipients are mixed and a wetting agent is introduced and a wet mass is formed. this is then reduced in size to form granules which are then dried and it proceeds on

Question 4

describe the process of dry granulation

Answer 4

mixture is compressed between rollers to produce a sheet or flakes of material. these are then reduced in size by milling which are then sieved to separate the required fraction.

Question 5

What are the advantages of wet granulation

Answer 5

relatively lower cost compared to dry granulation

combined purpose machines available

Question 6

what are the disadvantages of wet granulation

Answer 6

multiple machines used, mixer, granulator, dryer

effects of drying times and temperature on drug stability

hydrolysis of drug

Question 7

what are the advantages of dry granulation

Answer 7

can be used for materials sensitive to wetting

no drying

only one equipment

Question 8

what are the disadvantages of dry granulation

Answer 8

can reduce the compaction properties of the granules

primary powder flowability problems can be observed

segregation of the mixture can occur

Question 9

How does particle bonding work in wet granulation

Answer 9

adhesion and cohesion forces in immobile films cause inter particulate distance to decrease and increase the contact area where interfacial force in mobile liquid films which forms a solid bridge.

Question 10

How does particle bonding work in dry granulation

Answer 10

attractive forces between solid particles form and solid bridges form

Question 11

Describe the 4 steps of a shear granulator (wet granulation)

Answer 11

mixing of api + excip

formation of damp mass

granulation

drying

Question 12

what are the disadvantages of a shear granulator

Answer 12

long duration
different equipment for each step
have been replaced by more efficient granulators

Question 13

what is different about a high speed mixer

Answer 13

mixing wetting and granulator performed in one step

Question 14

what are the disadvantage of high speed mixer

Answer 14

end point monitoring system required

Question 15

describe the advantages of a fluidized bed granulator

Answer 15

all in one equipment
reduced labour cost
automation is possible

Question 16

describe the disadvantages of a fluidized bed granulator

Answer 16

initial cost
large number of parameters which affect the granules
optimisation and automation lengthy process

Question 17

describe the process of roller compaction

Answer 17

powder compressed between two rollers which have variable compression times. they then go to a oscillating granulator often used to break the sheet/ flakes to granules

Question 18

what are the advantages of roller compaction

Answer 18

ecological and cost effective

relatively low investment cost

easy to scale up

Question 19

what are the disadvantages of roller compaction

Answer 19

disadvantges not all materials respond well to roller compaction and may lose them in poor re compaction properties q

Question 20

what is the main advantage of extrusion

Answer 20

incorporate high level of api in a relatively small particulates

Question 21

describe the process of extrusion

Answer 21

mixing of the api + excips
wet massing
extrusion
spheronisation
screening

Question 22

What is melt granulation

Answer 22

granulation process which uses a thermosetting material (hot melt bind) to bind the powder particles into granules

Question 23

what are the advantages of melt granulation

Answer 23

no water or organic solvents used

Question 24

what are the disadvantages of melt granulation

Answer 24

thermal degradation

not many alternatives to PEGS

Question 25

what is drying

Answer 25

process by which liquid is removed from a wet solid

Question 26

what occurs during drying

Answer 26

heat is transferred to the wet material

solvent is transformed into gas and leaves the material

Question 27

what does drying of powders and granulates do

Answer 27

increases the stability and improves flowability