Study of formulation variables influencing polymeric microparticles by experimental design

The objective of this study was to prepare diclofenac sodium loaded microparticles using the single emulsion [oil-in-water (o/w)] solvent evaporation method. The 2 2 experimental design methodology was using the Design-Expert ® software used to evaluate the effect of two formulation variables on the properties of the microspheres in terms of particle size, morphology, encapsulation efficiency, and in vitro drug release. The graphical and mathematical analysis of the design showed that the independent variables had a significant effect on the encapsulation efficiency and drug release of microparticles. The low magnitudes of error and significant values of R 2 prove the high prognostic ability of the design. The microspheres showed high encapsulation efficiency with an increase in the amount of polymer and a decrease in the amount of PVA in the formulation. The particles were found to be spherical with a smooth surface. Prolonged drug release and enhancement of encapsulation efficiency of polymeric microparticles can be successfully obtained by applying experimental design techniques.