Preparation of PLGA microparticles by an emulsion-extraction process using glycofurol as polymer solvent

Purpose. To develop biodegradable poly(lactic-co-glycolic acid) (PLGA) microparticles prepared by an original emulsion-extraction process, with glycofurol, a nontoxic excipient, as polymer solvent. Methods. The preparation of microparticles consisted in dissolving polymer in glycofurol. This solution was emulsified in a vegetable oil, and then amphiphilic agent was added into the emulsion to extract glycofurol and lead to microparticle formation. Physicochemical studies were carried out, and an experimental design was prepared in order to elucidate the impact of the formulation composition on the microparticle characteristics. Finally, encapsulation tests were made with a model protein. Results. In a ternary diagram, a small feasibility area allowing particle formation was located. The resulting microparticles were spherical with a homogeneous, polymeric matrix structure. They exhibited a variable size from 3 to 15 mum, which was controlled by the different formulation parameters. Differential scanning calorimetry (DSC) analysis made it possible to detect their composition. Preliminary results showed that these particles were able to encapsulate a protein model, lysozyme. Conclusions. This simple and convenient technique enabled us to obtain spherical, biodegradable microparticles from acceptable excipients. Moreover, the process conditions made possible the encapsulation of drugs, including proteins.