Film Cracking

Coated tablets exhibit micro- or macroscopic cracks across the surface.

Tablet Core Tablet core expands when exposed to typical coating process temperatures.
  • Reformulate core to minimize or eliminate use of mineral excipients (calcium carbonate, calcium sulphate, calcium phosphate) that are prone to thermal expansion effects.
Tablet core absorbs water from coating liquid, causing expansion.
  • Reduce content of highly water absorbent excipients (such as microcrystalline cellulose).
Tablet undergoes significant post-compaction strain recovery.
  • Extend hold time after tableting process before coating.
Coating Formulation Formulation is not flexible enough to withstand tablet core expansion.
  • Consult with Ashland to select an Aquarius™ film coating formulation with increased flexibility.
Film coating does not have enough mechanical strength to withstand core expansion.
  • Consult with Ashland to select an Aquarius film coating formulation that has greater mechanical strength
Coating Process Tablet core expands due to excessive heating effects.
  • Reduce processing temperature and/or increase spray rate.
Tablet core expands due to absorption of water.
  • Improve drying capabilities of the coating process either by increasing process air temperatures, reducing spray rates, or both.
  • Increase pan speed to minimize dwell time in the spray zone.