milling and blending

Question 1

reason for size reduction

Answer 1

1) increase SA for reaction
2) improve extraction of active principles
3) improve dispersibility
4) allow better mixing or blending*
5) enable rapid dissolution*
6) preliminary process in preparation of productions *

• impt for solid dosage form

Question 2

what affect size reduction

Answer 2

mechanical- type of equipment
fracture mechanics of particles
properties of material

Question 3

advantage of wet grinding

Answer 3

1) eliminate dust
2) Easy to handle
3) use less energy
4) increase mill capacity

Question 4

Disadavantage of wet grinding

Answer 4

1) increase wear of grinding medium
2) not application to soluble material
3) may need drying of product

Question 5

size reduction process

Answer 5

1) fracture

2) abrasion

Question 6

factors affecting size reduciton

Answer 6

1) friability range (brittleness)
2) toughness
3) abrasiveness
4) hygroscopicity
5) explosiveness
6) corrosiveness

Question 7

Size reducion mechanism

Answer 7

1) impact (hammer)
2) compression (roller)
3) shear (knife edge)
4) attration

Question 8

advantage of hammer mill

Answer 8

1) several models available, verticl and horizontal designs
2) medium to high shear applications
3) blades and screens are interchangeable
4) suitable for very hard materials

Question 9

disadvantage of hammer mill

Answer 9

1) noisy and dusty
2) cannot plug feed
3) belt slip common due to load
4) high volume air generation, ventilation requirement
5) screen selection and installation complex and not scalable
6) sifting required after milling
7) temperature rise due to friction

Question 10

cone mill hole for wet dispersion

Answer 10

square hole

Question 11

round impeller in cone mill for ____–

Answer 11

Dry sizing

Question 12

squareimpeller in cone mill for ____–

Answer 12

wet and dry sizing

Question 13

micronization mill

Answer 13

vibratory ball mill
air jet mill
fluid energy mill

Question 14

loading methods

Answer 14

1) always consistent
2) layering reduces the number of blend revolution
3) layer large volumes of exvipient or active
4) lubricants do not normally require layering and tend to improve flow properties and may help blend cohesive products

Question 15

essential for excipients and base materials to be within reasonable specifications otherwise it could lead to differing blend parameters

Answer 15

essential for excipients and base materials to be within reasonable specifications otherwise it could lead to differing blend parameters

Question 16

issues to consider when using vibration IBC

Answer 16

1) compaction
2) segregation
3) noise
4) IBC damage
5) weighing systems
6) dosing capability
7) production residue

Question 17

blending critical parameter

Answer 17

1) number of revolution
2) % fill
3) loading method
4) sampling method
5) formulation

• simple scale up process
• contained process

Question 18

NIR benefit

Answer 18

1) safe
2) no sampling error
3) real time information
4) multi ingredient uniformity
5) process understanding
6) process finger - printing for scale up
7) right first time
8) fast release of the blend - reduced cycle times