Effects of supercritical carbon dioxide processing on optical crystallinity and in vitro release of progesterone and Gelucire 44/14 solid and semi-solid dispersions

The aim of this study was to determine the effect of supercritical carbon dioxide (SC-CO2) on the crystallinity and drug release of Gelucire 44/14-based endogenous progesterone (PGN) dispersion systems. The light scattering from PGN crystals incorporated in Gelucire 44/14 was imaged using optical microscopy. In vitro dissolution was used to determine the release kinetics of PGN, Gelucire 44/14, incorporated by a supercritical fluid (SCF) method. Release profiles were evaluated according to zero-order, first-order, Higuchi, Krosmeyer-Peppas, and dual first-order models. The dual first-order release model illustrated two distinct release rates: an initial rapid release followed by a slow diffusion of PGN from the dispersion systems. The dual first-order release model adds a new tool to the elucidation of release mechanisms from lipid and micelle-forming-based dispersion systems, where parallel processes contribute to drug release.