Assessment of blending performance of pharmaceutical powder mixtures in a continuous mixer using Discrete Element Method (DEM)

This study proposes a new sample-independent mixing index, termed the Coefficient of Blending Performance (CBP), for monitoring the formation of undesired API (Active Pharmaceutical Ingredient) agglomerates in continuous mixing processes. The proposed index is examined for the blending of pharmaceutical powders in a simulated twin-screw mixer using Discrete Element Method (DEM). Model excipient and API particles with physical and mechanical properties within the typical range of pharmaceutical powders are used in simulations. Results suggest that the CBP is an effective index for monitoring the formation of API agglomerates in the mixer. Using this index, DEM results suggest a high possibility of formation of API agglomerates during the first stage of twin screw mixing. The results show that adding a kneading zone to the twin screw mixer enhances the blending quality by breaking the API agglomerates, making the mixture ready for the next operating unit.