Granulation

Question 1

What is granulation?

Answer 1

A process to agglomerate powder to form larger particles and increase stability

Question 2

Why is granulation used?

Answer 2

Prevent powder mix segregation 
improve powder flow
improve compaction
reduce dust formation
improve electrostatic interactions
makes handling, storage and transfer easier
Improves wettability
Improves bulk density

Question 3

Describe the process of dry granulation?

Answer 3

1. Mixing
   Mixing of the drug compound and excipients
2. Compaction/aggregation
   2 processes used
   Slugging- rollers with concave depressions
   Rollers- smooth rollers compact powder mix forming continuous sheet
   Aggregate under high pressure by compaction
3. Drying/milling
   Large agglomerates are milled to the desired particle size
4. Screening
   Sieves used to obtain the right granule size
   Removes any powder generated from the desired particles
   0.2-0.5mm desired

Question 4

Describe the process of wet granulation?

Answer 4

1. Mixing
   Mixing of the drug compound and excipients
2. Compaction/aggregation
   2 processes used
   Slugging- rollers with concave depressions
   Rollers- smooth rollers compact powder mix forming continuous sheet
   Aggregate by adding solvent or binder
3. Drying/milling
   Solvent removed to leave behind large agglomerates
4. Screening
   Sieves used to obtain the right granule size
   Removes any powder generated from the desired particles
   0.2-0.5mm desired

Question 5

What aggregation forces hold together agglomerates?

Answer 5

Cohesive interparticular interactions
Liquid bridges
Solid bridges