AEROSOL SOLVENT-EXTRACTION SYSTEM - A NEW MICROPARTICLE PRODUCTION TECHNIQUE

The aerosol solvent extraction system (ASES) utilises the extraction properties of supercritical gases for the production of microparticles. Extraction with supercritical gases is frequently used in the food industry and in analytical chemistry. In the ASES process drug and polymer are dissolved or dispersed in an organic solvent which is sprayed into a supercritical gas phase (e.g., carbon dioxide). The organic solvent is soluble in the supercritical gas phase and is extracted resulting in the formation of solid microparticles. Different biodegradable polymers, poly(DL-lactide) (PDLA), poly(DL-lactide-co-glycolide) (PGLA) with lactide/glycolide ratios (50: 50) and (75: 25), poly(L-lactide) (PLA) and poly(beta-hydroxybutyric acid) (PHB) were tested for their suitability in ASES. The polymers PDLA and PLGA (75:25) were extracted. The use of PLGA (50:50) led to partial extraction and a polymer film in the collecting vessel. Microparticles were obtained using PIA and PHB. The particles were spherical and the particle size range (X50%) was 1-10 mum.