Weight variation

what is the reason of weight variation of tabs during compreson?

Machine:
Die fill weight is not exactly same
Precompression and main compression force also varies each tooling.

Powder:
Very hard granules
very low flow property.

Thanks

good
more precisly
Machine
Inproper filling due to
speed
poor feeding system
poor hooper design
Formulation
Flow problem due to
lack of glident
rat hole
more fine less grains
more grains less fine

what’s ratio of fine and grains particles?

usualy 80-85% grain
15-20% fine

2 Likes

In my opinion, with experiences: 60% grain - 40% fine is the best ratio in most cases. Just a few grains can cause weight variation so we need to make a minimum grain that can assure the flowability.

40% is very high ratio.

what should be the grain size?

its depend upon dissolution profile and tablet weight.

Reason of weight variation of tabs during compression are

  1. Formulation: Poor flow of granule, BD variability, TD variability etc.
  2. Machine : Faulty feeding/hopper system, pre-compression and main compression force variability etc
1 Like

moisture content also relates with weight variation…isn’t it?

1 Like

yes
up to some extent indirect role