Prediction of Granule Critical Quality Attributes Using Twin Screw Granulation

Wet Granulation is a commonly used unit operation for particle size enlargement of fine powders to mitigate issues such as blend segregation, dust formation, and poor flowability. Twin Screw Granulation is a robust and continuous approach towards performing wet granulation at various scales of operation. A predictive understanding of the granule properties in Twin Screw Granulation is becoming increasingly important in order to ensure a Quality-by-Design approach in the wet granulation and downstream processes.

Granule breakage is found to be the dominating rate process in Twin Screw Granulation. We have performed breakage isolating experiments to understand the influence of formulation properties, process parameters, and screw design on granule breakage characteristics, specifically, granule breakage probability and daughter size distributions. A model has been proposed for the breakage rate process in Twin Screw Granulation, based on the results from the breakage isolating experiments. We have used screw pullout experiments to understand the development of the critical quality attributes of the granules as a function of the axial distance from the end of the granulator. These experiments provide further insight into the granulation mechanisms in different screw element designs. The results from the screw pullout experiments are consistent with the granule breakage model deduced from the breakage isolating experiments.