Supercritical CO - assisted production of PLA and PLGA foams for controlled thymol release.

Amorphous, medical grade poly(d,l-lactic acid) (PLA) and poly(d,l-lactic-co-glycolic acid) (PLGA) were used to develop systems for controlled release of a natural bioactive substance - thymol. Supercritical carbon dioxide (scCO) was successfully used both as an impregnation medium for thymol incorporation into the polymer matrix and a foaming agent in a single-step batch process. Impregnation of samples using low to moderate scCO densities (273 kg/m and 630 kg/m) and short processing times (2 h and 4 h) enabled thymol loading of 0.