Excessive Roughness (Orange Peel)

The surface of the applied film coating is extremely rough, often taking on the appearance of the skin of an orange.

ISSUE CAUSES RECOMMENDATIONS
Coating Formulation Coating formulation is too viscous, or is not atomizing effectively.
  • Consult with Ashland to select an Aquarius™ film coating formulation that produces lower viscosity coating suspensions and/or atomizes more finely under typical process conditions. Learn more.
Coating Process Coating suspension is not atomizing effectively.
  • Consider reducing the solids concentration to reduce viscosity.
  • Optimize the atomizing air pressure/volume to get more effective atomization.
  • Ensure that spray gun setup has been optimized so that there is no mis-spraying, that all spray guns are spraying at the same rate, and the gun-to-bed distance is optimal and consistent for each spray gun.
  • Ensure that drying conditions and spray rates are balanced to minimize any spray-drying effects.
Overwetting of the tablet bed is occurring, causing film rubbing.
  • Ensure that spray gun setup has been optimized so that there is no mis-spraying, that all spray guns are spraying at the same rate, and that each is providing the same area of coverage over the tablet bed surface.
  • Decrease spray rate and/or increase processing temperature.
  • Increase pan speed to reduce dwell time in the spray zone.