fluid bed

Question 1

mechanism of granualtion in fluid bed

Answer 1

1) droplet formation
2) evaporation
3) sticky droplets contact powder particles
4) open lattice ‘snowflake’ type granule
- good binder distribution
- good compressibility

Question 2

choice of binder, viscosity and concentration play an important effect on granule formation and growth

Answer 2

choice of binder, viscosity and concentration play an important effect on granule formation and growth

Question 3

characteristic of FB granule produced

Answer 3

1) open structure
2) bulk density similar to raw materials
3) good distribution of binder on surface
4) uniform and narrow particle size distribution
5) good texture

Question 4

FB granulation is effective at production good quality granules, free-flowing and compressible

Answer 4

FB granulation is effective at production good quality granules, free-flowing and compressible

Question 5

why drying?

Answer 5

1) to form a free flowing powder
2) to remove moisture (or organic solvent)
3) to condition/improve characteristic of product for the next process step

Question 6

FSD fluid spray drying is ?

Answer 6

one step operation for the production of granues from liquid

produce granules suitable for direct compression

mix all ingredients in the liquid phase as a solution/suspension to spray dry and produce granules

Question 7

benefits of microwave

Answer 7

1) penetrates into the product: drying at the core of the granules

2) does not depend on heat conduction
3) instant energy source
4) heat liquid (water and solvent) rarely the product
5) no effect on majority of granulation compounds

Question 8

cons of microwave vacuum drying

Answer 8

1) limits for temperature sensitive products which require a very low residual moisture content
2) technique is still relatively unknown, which may lead to acceptance problems by the customer (NOT WITH REGULATORY BODIES)

3) more complicated and expensive

Question 9

pros for microwave vacuum drying

Answer 9

1) energy supply independent from vessel wall, wall temperature can be controlled in order to avoid caking

2) no risk of wet lumps
3) significantly reduced drying time
4) scale up of drying time is linear (depending on microwave power installed)

Question 10

drying too fast can influence granule quality

Answer 10

1) explosion of granule due to evaporation of liquid

2) if a gelling agent is used (eg HPMC) no time to hydrate so no time to bind (no bridge form)

Question 11

spray drying produces

Answer 11

porous, spherical granules.

Question 12

fluid bed granules

Answer 12

highly compressible and spherical