A NOVEL EMULSIFICATION-SOLVENT EXTRACTION TECHNIQUE FOR PRODUCTION OFPROTEIN LOADED BIODEGRADABLE MICROPARTICLES FOR VACCINE AND DRUG-DELIVERY

This paper describes the preparation of poly(lactide-co-glycolide) (PL G) microparticles containing ovalbumin (OVA) as a model antigen, using three different approaches; based on solvent evaporation/extraction t echniques. These are respectively: (1) water-in oil-in water (W/O/W), (2) water-in oil-in water-in oil (W/O/W/O),and (3) water-in oil-in oil (W/O/O). The effects of process parameters on particle size, surface morphology, protein entrapment and release properties are presented. T he use of methanol as the continuous phase results in a protein entrap ment level of approximately 10% (w/w) in 10 mu m microparticles and th e microparticles retain good spherical form. This successful use of an organic continuous phase, which is miscible with the polymer solution , offers the prospect of enhancing the protein loading capacity of res orbable polylactide microparticles and of improving the delivery of ef fective doses of vaccine and therapeutic proteins and peptides. Ovalbu min appears to act as a surfactant in the water-in oil-in oil method. This has implications for protein release and vaccine performance.