High shear blending with glyceryl distearate provides individually coated drug particles for effective taste masking
Lipid coating in a high shear blender without heating and complex spray mechanism was investigated as a simplified approach to hot melt coating in a fluid bed device. Potassium chloride was coated with 20% glyceryl distearate using both processes. Microscopic images revealed that the drug surface was covered with a smooth lipid film after processing in the high shear blender as opposed to an irregular film obtained by fluid bed coating. Particle size analysis showed that blending speed had a significant impact on particle growth. Fast blending at 750 rpm resulted in particle agglomeration whereas blending at 450 rpm provided individually coated drug particles. In vitro dissolution studies indicated that both processes were able to keep potassium chloride concentration below an indicative taste perception threshold. Negative sensory characteristics were shown to be reduced in both processes. The results suggest that lipid coating in a high shear blender is as efficient as hot melt coating in a fluid bed device, but offers the benefit of being much simpler. This enables the production of high dose drugs with reduced bitter taste at low excipient concentration and therefore has the potential to improve oral treatment, in particular for pediatric patients.