Encapsulation of protein-loaded hydroxyapatite granules with poly (lactic-co-glycolic acid)

Abstract

A solid-in-oil-in-water (S/O/W) emulsion-solvent evaporation method was applied to encapsulate protein-loaded hydroxyapatite (HAp) granules (D 50 = 19.5 μm) with a biodegradable polymer of poly (laetic-eo-glyeolie acid) (PLGA), After loading bovine selum albumin (BSA), the HAp granules were mechanically dispersed in oil phase (PLGA dissolved in CH 2Cl2), and then the suspension was dropped into water containing an emulsion stabilizer of polyvinyl alcohol (PVA), Stirring of the dropped suspension in the water phase produced S/O/W emulsions. The emulsions were diluted with excess water to facilitate removal of the organic solvent (CH2Cl2) from the oil phase. After the evaporation of CH2Cl2, the particulate materials were separated, washed and vacuum-dried. The resultant particles had very smooth PLGA surface with spherical shape, and their mean particle size was about several microns larger than that of the HAp granules. Fluorescently-labeled confocal laser scanning microscopy (CLSM) revealed that the protein-loaded HAp granules were encapsulated in the PLGA microsphere.