When powder properties are unsuitable for direct compression, a granulation step is required to improve compactibility, flow, and content uniformity.

Lipid excipients are commonly used in two granulation techniques to modify drug dissolution, either as sustained-release or wetting agents:

  • wet granulation—where the solid lipid excipient is used in the powder blend or incorporated into the binder solution
  • melt granulation—where the lipid excipient acts as a binder between the solid particles (ingredients are blended as temperature is brought gradually up to the lipid melting point to form granules)

Advantages of lipid excipients in wet granulation:

  • organic solvent–free process
  • water-insoluble atomized powders prevent swelling and sticking during granulation
  • waxy, water-dispersible Gelucires incorporated into aqueous binder solution
  • easy cleaning of equipment and tooling

Advantages of lipid excipients in melt granulation:

  • solvent-free process
  • high binding capacity, yielding resistant granules
  • flexible process, suitable for high shear mixer, melt extruder, and fluid bed granulator

Range of functional excipients for granulation:

A Gattefossé in-house study of continuous granulation via extrusion has demonstrated that

  • hot melt granulation is achievable using a twin-screw extruder simply without the die;
  • granule particle size can easily be adjusted by adapting the extrusion temperature profile and feed rate.


Two cases studies are available:

  • ibuprofen / Compritol® 888 ATO (9:1 ratio)
  • tramadol hydrochloride / Compritol® 888 ATO


Watch the video on continuous granulation with Precirol® ATO 5