THE IMMUNOGENICITY OF A MODEL PROTEIN ENTRAPPED IN POLY(LACTIDE-CO-GLYCOLIDE) MICROPARTICLES PREPARED BY A NOVEL PHASE-SEPARATION TECHNIQUE

A novel phase separation technique was used to prepare poly(lactide-co-glycolide) microparticles with an entrapped model protein, ovalbumin (OVA). In an in vitro release study, the entrapped OVA showed controlled release from the microparticles over about 10 to 15 days. Following subcutaneous (s.c.) immunization in mice, the microparticles induced a serum IgG antibody response that was significantly enhanced in comparison to the response induced by soluble OVA and was comparable to the response induced by OVA adsorbed to an aluminium hydroxide adjuvant. The microparticles were also immunogenic by the oral route in mice and induced a serum IgG antibody response that was half the maximal response induced by s.c. immunisation with OVA adsorbed to the adjuvant.