Facile fabrication of biocompatible PLGA drug-carrying microspheres by O/W pickering emulsions

This study is focused on the preparation of Ibuprofen (IBU) loaded micrometer-sized poly(lactic-co-glycolic acid) (PLGA) microspheres and process variables on the size, drug loading and release during preparation of formulation. Silicon dioxide (SiO2) nanoparticle-coated PLGA microspheres were fabricated via a combined system of Pickering-type emulsion route and solvent volatilization method in the absence of any molecular surfactants. Stable oil-in-water emulsions were prepared using SiO2 nanopartides as a particulate emulsifier and a dichloromethane (CH2Cl2) solution of PLGA as an oil phase. The SiO2 nanoparticle-coated PLGA microspheres were fabricated by the evaporation of CH2Cl2 in situ, and then bare-PLGA microspheres were prepared by removal of the SiO2 nanoparticles using HF aqueous solution. The two types of microspheres were characterized in terms of size, component and morphology using scanning electronic microscope (SEM), Fourier-transform infrared, optical microscope, and so on. Moreover, IBU was encapsulated into the hybrid beads by dispersing them in the CH2Cl2 solution of PLGA in the fabrication process. The sustained release could be obtained due to the barrier of the polymeric matrix (PLGA). More over, the release curves were nicely fitted by the Weibull equation and the release followed Fickian diffusion. The combined system of Pickering emulsion and solvent volatilization opens up a new route to fabricate a variety of microspheres. The resulting microspheres may find applications as delivery vehicles for biomolecules, drugs, cosmetics and living cells. (C) 2011 Elsevier B.V. All rights reserved.