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


A. Bayly, A. Hassanpour, M. A. Behjani, Y.G. Motlagh




Powder Technology



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 sensitivity of the proposed index is tested on a DEM-simulated twin-screw blending of pharmaceutical powders with a novel mixing design. Model excipient and API are used in simulations with their physical and mechanical properties being within the typical range of properties of generic pharmaceutical powders. 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.


Active pharmaceutical ingredient, Agglomeration, Discrete element method, Mixing index, Surface Energy, Twin screw mixer

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