Influence of formulation and process parameters on the characteristics of PLGA-based microparticles with controlled drug release.

PLGA microparticles for sustained release of ibuprofen as the model drug were prepared by the O/W solvent evaporation method under altering stirring speed (600, 1000 rpm), emulsifier concentration (PVA concentration 0.1%, 1%) and organic solvent selection (dichloromethane, ethyl acetate). The obtained results confirmed the effect of selected formulation and process parameters on the properties of prepared PLGA-based microparticles. An influence on encapsulation efficiency, yield, morphological properties, mean size and drug release was observed. Increased stirring speed within the solvent evaporation process resulted in a decrease of encapsulation efficiency, yield and mean size but the incorporated drug was released faster. Increased PVA concentration in the external emulsion phase brought the same results except the ibuprofen release rate. Microparticles prepared with dichloromethane as the organic solvent exhibited higher sphericity, a more regular shape with a smooth surface, and thus dichloromethane was considered to be a more suitable organic solvent in comparison with ethyl acetate for this purpose.