Vibrio cholerae -loaded poly(DL lactide co-glycolide) microparticles

Vibrio cholerae (VC)-loaded microparticles were prepared using poly(DL lactide-co-glycolide) with a water-in-oil-in-water emulsion/solvent extraction technique. Particle characteristics including size distribution, VC-loading efficiencies, and in-vitro release pattern were investigated. The dispersed phase was PLG dissolved in dichloromethane, and the continuous phase was water containing PVP as a stabilizer with varied sodium chloride concentrations. VC was successfully entrapped in the microparticles with trapping efficiencies up to 97.8%, a loading level of 55.4 g/mg, and particle size of 3.8 #181;m. Using 10% w/v PVP with 5% w/v NaCl in the continuous phase resulted in a higher loading level (55.4 #45 6.9 g/mg), loading efficiency (97.8%), core region content (25.7 #45 1.9 g/mg) and lower surface content (6.2 #45 0.9 g/mg) than without NaCl (loading content: 40.7 #45 5.1 g/mg; loading efficiency 52.1%; core region content: 8.3 #45 0.5 g/mg; surface content: 19.5 #45 1.1 g/mg). A linear release profile from VC-loaded microparticles was found. A preliminary animal oral administration study indicated that the VC-loaded microparticles, as an oral delivery system, have shown effective immunogencity in rats for 2 months. The VC incorporation and physicochemical characterization data obtained in this study may be relevant in optimising the vaccine incorporation and delivery properties of these potential vaccine targeting carriers.