Preparation of monolithic matrices for oral drug delivery using a supercritical fluid assisted hot melt extrusion process

The use of supercritical fluids as plasticisers in polymer processing has been well documented. The body of work described in this research paper outlines the use of a supercritical CO2 assisted extrusion process in the preparation of a hot melt extruded monolithic polymer matrix for oral drug delivery. Several batches of matrix material were prepared with Carvedilol used as the active pharmaceutical ingredient (API). These batches were subsequently extruded both with and without supercritical CO2 incorporation. The resultant matrices were characterised using steady-state parallel plate rheometry, differential scanning calorimetry (DSC), atomic force microscopy (AFM), micro-thermal analysis (RTA) and dissolution testing. Dissolution analysis showed that the use of supercritical CO2 during the extrusion process resulted in a faster dissolution of API when compared with unassisted extrusion. The supercritical CO2 incorporation also resulted in reduced viscosity during processing, therefore allowing for quicker throughput and productivity. The results detailed within this paper indicate that supercritical fluid assisted hot melt extrusion is a viable enhancement to conventional hot melt extrusion for the production of monolithic dosage forms. (c) 2006 Elsevier B.V. All rights reserved.