The double-layered microsphere: Encapsulation of water-soluble protein with PLGA

The double-layered microspheres play an important role in controlling drug delivery for pharmaceutical application, because of the low initial burst compared with single-layered spheres and targetable delivery to specific organ. But it has drawback in loading drug and controlling size. In this study, we developed double-layered spheres using relatively simple oil-in-water (O/W) solvent evaporation method using bovine serum albumin (BSA) as water-soluble protein and poly(D,L-lactide-co-glycolide) (PLGA). BSA/PLGA double-layered microspheres were fabricated using O/W solvent evaporation method and investigated the specific character of double-layered microspheres according to the kind of surfactants. In SEM observation, double layered microsphere had spherical shape and smooth surface without pores. And the double layered microsphere using O/W solvent evaporation method was transparency because of slow evaporation of solvent. In fluorescent observation, we observed the fluorescent core in the double-walled spheres composed of FITC-BSA and PLGA using fluorescent observation. In the case of polyvinylalcohol as emulsifier, the yield was better than gelatin. As decreased concentration of PLGA, the size of double-layered microspheres deceased.