Supercritical fluid encapsulation of acizol into aliphatic polyether microparticles

Encapsulation of pharmaceutical grade acizol (Acizol® pharmaceutical substance) into bioresorbable D,L-polylactide and polylactoglycolide microparticles using supercritical carbon dioxide has been studied. An effective way for formation of polymer fine powders (mean particle size of about 10–20 µm) containing up to 20 wt % of the bioactive component without any organic solvent used has been suggested. Raman spectroscopy with spatial resolution was employed to analyze the distribution of acizol throughout the volume of the individual polymer microparticles and to study the kinetics of its release into saline. The rapid release (40–80% of the total amount of the encapsulated substance) from the samples under study was observed during the first hour, and then it was followed by a gradual, almost linear release between the 4th and 14th days of the experiment, with the total release continuing up to 100%.