Effects of processing parameters and blade patterns on continuous pharmaceutical powder mixing

The present study summarizes the experimental characterization of a new continuous powder mixer (GCG-70 by Glatt (R)) using common pharmaceutical ingredients. The powder hold-up and residence time distribution were used to characterize the bulk behavior of the mixer as a function of impeller rotational speed, total throughput (mass flow rate) and blade configuration. The relative standard deviation (RSD), calculated from samples taken at the outlet of the blender, was used to characterize its mixing performance. The hold-up and the mean residence time decreased with increasing impeller rotational speed. The mean centered variance and the number of blade passes increased with increasing impeller rotational speed. The effect of the blade configuration on the mixing dynamics diminished as the rotation rate increased. The hold-up and mean residence time were sensitive enough to demonstrate the effects of blade configurations. The mixing performance, depending on the processing parameters, was found to be between 5% and 10% RSD for 5% w/w active pharmaceutical ingredient (API), and <3% for 30% w/w API. These results showed improvements in the mixing performance when compared to studies of other continuous mixers using similar materials and analytical techniques for quantification. (C) 2016 Elsevier B.V. All rights reserved.