A novel preparation method for polymeric microparticles without the use of organic solvents

Microparticles (microcapsules and microspheres) of different chemical compositions (methacrylated dextran, methacrylated poly(ethyleneglycol) and gelatin) were prepared using a novel emulsion technique based on polymer–polymer immiscibility in aqueous solutions. The effect of polymer chemical composition and crosslink density on the properties of the microspheres was evaluated. Microparticles with a volume mean diameter ranging from 2.5 to 25 μm could be prepared in a reproducible way. Scanning electron microscopy revealed that non-porous and spherical particles were obtained for all preparations. Microcapsules with a single core were prepared using a double emulsion technology, based on the same principle of polymer–polymer immiscibility. These results demonstrate that this new emulsion technique without organic solvents can be used for the preparation of well-defined microparticles differing in size, morphology and chemical composition.