Twin screw granulation – review of current progress

Abstract

Twin screw granulation (TSG) is a new process of interest to the pharmaceutical community that can continuously wet granulate powders, doing so at lower liquid concentrations and with better product consistency than found by a high shear batch mixer. A considerable body of research has evolved over the short time since this process was introduced but generally with little comparison of results. A certain degree of confidence has been developed through these studies related to how process variables and many attributes of machinery configuration will affect granulation but some major challenges still lay ahead related to scalability, variations in the processing regimes related to degree of channel fill and the impact of wetting and granulation of complex powder formulations. This review examines the current literature for wet granulation processes studied in twin screw extrusion machinery, summarizing the influences of operational and system parameters affecting granule properties as well as strives to provide some practical observations to newly interested users of the technique.

• Continuous manufacturing
• foam granulation
• solid oral dosage forms
• twin screw granulation
• wet granulation

Acknowledgements

The author wishes to make particular mention of thanks to Paul Sheskey who mentored him in pharmaceutical formulation and to his current collaborator, Kevin O’Donnell at The Dow Chemical Company who inspires new directions of exploration.

Declaration of interest

The author of this manuscript declares no conflicts of interest. The author is gratefully to the funding by the Natural Science and Engineering Research Council of Canada (NSERC), Discovery grant RGPIN/249687-2012 as well as to the generous donations of materials and technical expertise given to his research in wet granulation by The Dow Chemical, BASF, Evonik and FMC Biopolymers.