An Investigation of Mixing Performance of a Continuous Powder Mixing Process

Continuous manufacture of drug products is receiving increased attention both from academics and industry in recent years.  Pfizer’s approach to continuous manufacture, utilizing a Portable, Continuous, Miniature and Modular (PCM&M) technology is the focus of this presentation.  In this work, the performance of a novel, vertical in-line powder mixing technology will be described.  This mixer, which offers the independent selection of mixer shear rate, powder hold up mass and system mass throughput, is studied both experimentally and computationally to first characterize the mixing performance and secondly better understand how process parameters and equipment design can be manipulated to achieve the desired performance.  The links between process conditions, powder flow regime, and mixing performance are illustrated with experimental data.  Discrete element method (DEM) simulations are used to further characterize the mixer operation with respect to mixing performance and the extent of powder lubrication under a variety of conditions.  Additionally, the models are used to characterize the coupled impact of gravimetric feeder variability and mixer performance (residence time distribution) on the variability in the outlet stream concentration.  Together, these simulations also provide grounds to assess the influence of various design considerations on performance of the PCM&M equipment train.