granulaiton

Question 1

wet agglomeration

Answer 1

wet massing by planetary or HSM, extrusionand pelletization

Question 2

agglomerate growth through continuous agitation

Answer 2

balling, fluid bed

Question 3

LSM

Answer 3

humidification and vacuum drying

Question 4

types of granulation method

Answer 4

1) direction compression
2) wet granulation —-> sphere
3) dry granulation
4) thermoplastic granulation –> sphere

Question 5

particle size of primary component

compare particle size

Answer 5

smaller particles requires higher amount of binding liquid than larger particles,
because
smaller particle usually more difficult to densify to due higher packing density and SA higher

Question 6

component particle size on end product

Answer 6

smaller particles are favored in producing agglomerates that are more spherical, with smoother surfaces and of narrower size distributions

smaller particles also generally produce stronger agglomerates

Question 7

packing properties affected by

Answer 7

particle shape
irregular shape cr8 interlocking among particles and thus increase agglomerate strength whereas a rounder particles reduces the strength

Question 8

Direct compression

advantage and prerequisit

Answer 8

1) most effective and efficient method to prepare free flowing powders for tableting, mix and blend, without the additional step to increase particle size

requires material w

• suitable flow
• narrow size distribution
• minimal segregation and good compressibility

Question 9

major advantage of dry granuatin by roller compaction wet granulation methods

Answer 9

• few unit processes ,thus lower production cost
• suitable for heat and or water sensitive material
• a feasible process for preparing controlled release product

Question 10

bonding mechansim in dry granulation

Answer 10

1) particle rearrangement
2) particle fragmentation
3) particle bonding

Question 11

adv roller compaction

Answer 11

1) simple direct processing
2) eliminates granulating solvent
3) less energy and manpower to operate
4) allows continuous manufacturing
5) useful for heat/moisture sensitive products

5) vacuum to suck air , air can cause breaking??

Question 12

critrical operation attribution for roller compaction

Answer 12

1) screw feed rate
2) roll speed
3) roll pressure
4) roll gap

Question 13

compaction zone

Answer 13

1) slip region
particle begin slipping at the roll surfaces, some plastic
deformation of solid occurs

2) nip angle region
densification occur

3) release region:
immediate after powder compaction, size depends on extend of powder’s (compact’s) elastive recovery

Question 14

factors affecting compact strength

Answer 14

1) applied pressure
2) extend of air entrapment (use vacuum system)
3) roll dwell time
4) powder void fraction (space into which air is compacted)
5) particle size of component and density
6) type of binders included
7) moisture content of material

Question 15

purpose of wet granulation

Answer 15

1) improve flow properties
2) reduce bulk volume, densification
3) improve compression properties
4) improve distribution of a minor constituent eg low dose drug binder, colorant
5) prevent components from segrating
6) reduce dust
7) minimise or mitigate adverse properties of API
eg hydrophobicity, bad taste, poor stability

Question 16

disadv of wet granulation

Answer 16

1) additional processing steps, adds complexity, cost, extra validation work
2) additional time and space needed
3) unsuitable for moisture-sensitive or thermolabile drgs
4) material loss due to additional processing steps

Question 17

types of LSM and HSM

Answer 17

LSM
planetary mixer
orbiting

HSM
HSG

Question 18

low mean particle size + wide size distribution

Answer 18

pack well and high strength

mechanism

1) nucleation
2) coalescence

Question 19

large paricle size + narrow size distributino

Answer 19

low strength

mechanism

1) nucleation
2) layering

Question 20

Main granule growth mechanism

Answer 20

• nucleation

- coalescence

Question 21

seconfary growth mechanisms

Answer 21

• layering from degradation of existing particles

- ball growth

Question 22

requirements for successful granulation

Answer 22

1) dissolution of solids by solvent, and later the solute forms crystaline bridges when dried
2) dissolved binder in the granulating liquid may also by responsible for the formation of solid bridges
3) solid bridge formed the binding structure between particles

if solid bridges are absent, granules will revert back to the original powder

Question 23

Process steps of granulation by HSM

Answer 23

1) mixing of dry powder at high impeller speeds for 2-5min

2) additional of liquid binders, lower speeds, 1-2min
3) wet massing, high speeds, 1-5min
4) wet sieving of granules usually using cone mill
5) drying usually by fluid bed dryer
6) regranulation by cone mill

Question 24

adv of HSM granulaiton

Answer 24

1) short process time
2) less binder needed, therefore, shorter drying time
3) suitable for cohesive materials as well dense production

4) less sensitive to raw material physical attributes than fluid bed granulation
5) closed system: GMP, possibility for vacuum, microwave drying
6) easy to clean, CIP possible

Question 25

problems associated with HSM granualtors

Answer 25

1) mechanical degradation of weak powders and granules
2) some heat generation, unsuitable for thermolabile products
3) risk of over-wetting leading to uncontrolled growth.

Question 26

process variable for HSM

Answer 26

1) Impeller rotation speed (tip speed)
2) chopper rotation speed
3) load
4) liquid addition method
5) liquid addition rate
6) wet massing time