Twinning

It is a tablet coating defect, where 2 or 3 tablets stick together like twin baby.


Causes

  • High spray rate
  • Large droplet
  • Low pan speed
  • Inappropriate table shape 
  • Improper drying


Remedies

  • Reduce spray rate
  • High atomization
  • Increase pan speed
  • Select correct table shape
  • Proper drying




Blistering

Blistering of a coating surface occurs when the film becomes detached from the tablet’s substrate.


Causes

  • High temperature during spraying and drying


Remedies

  • Operate at mild drying conditions



Picking

Picking is a coating problem where a part of the film sticks to the pan resulting to some of the tablet pieces being detached from the core.


Causes

  • High spray rate
  • Low pan speed
  • Inadequate drying
  • Over-wetting of tablets


Remedies

  • Proper drying process
  • Low spray rate
  • Optimum pan speed
  • Increase viscosity of coating solution