Development and evaluation of microsphere based topical formulation using design of experiments

Abstract

The aim of this work is to develop microsphere formulation and study the impact of drug-polymer ratio, surfactant concentration and stirring speed on particle size and drug entrapment during preparation. Clotrimazole loaded Eudragit S100 microspheres were prepared by emulsion solvent evaporation method. A three level factorial Box Behnken design was used to characterize and optimize the formulation. The result of analysis of variance test indicated that the test is significant. The optimum drug: polymer ratio (X1), surfactant concentration (X2) and stirring speed (X3) was found to be 1:4, 1.5% and 1000 rpm respectively to obtain particle size and maximum entrapment efficiency of microspheres as 35.6 μm and 83.3%, respectively. The drug release from microsphere based cream exhibited a controlled release pattern.