Supercritical fluid fabrication of components for a sustained-release injectable risperidone dose form

Abstract

The process of supercritical fluid encapsulation of pharmaceutical grade risperidone into bioresorbable D,L-polylactide microparticles via the PGSS (Particles from Gas-Saturated Solutions) method was examined. Micronization and changes in the morphology of risperidone crystals during its encapsulation into a polymer plasticized with supercritical carbon dioxide were experimentally observed. This result made it possible to prepare the polymer structures of various dispersities (from 10 to 100 μm) and morphologies containing up to 40 wt % of risperidone without the use of organic solvents. The kinetics of release of risperidone from polymer microparticles in saline solution was studied by UV spectrophotometry. It was shown that the use of D,L-polylactides of various molecular weights makes it possible to achieve a controlled increase in the time of release of risperidone from bioresorbable polymer particles prepared via the PGSS technique up to ten days.