Hollow porous poly(lactic acid) microspheres

On the basis of the water solubility of poly(N-vinyl-2-pyrrolidinone), hollow porous poly(lactic acid) microspheres (HPPLAs) were prepared by a water-in-oil-in-water multiple-emulsion solvent evaporation method. The influence of the concentration of the stabilizer Span80 in the oil phase on the morphology was investigated. It was found that when the content of Span80 solutions was 3.5 wt %, most HPPLAs were about 2 μm in diameter. Field scanning electron microscopy results show that the HPPLAs were porous and hollow. The structure and crystal form of the HPPLAs were characterized by Fourier transform infrared spectroscopy and X-ray diffraction analysis. Using these HPPLAs as degradable templates, we successfully synthesized Litchi-like polystyrene (PS) microspheres about 2 μm in diameter by the emulsion method. When used as drug carriers, these HPPLAs would be convenient in which to embed drugs, whereas the Litchi-like PS microspheres may have potential as new materials for polymer modification. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2008