Response Surface Methodology for the Optimization OF Ethylcellulose Microspheres

One of the major challenges in developing a highly effective experimental plan to optimize the design space of a manufacturing process is the highly complex nature of the pharmaceutical manufacturing processes. Response surface methodology (RSM) techniques are widely used in pharmaceutical research and are the method of choice for demonstrating robust process which is as per regulatory requirements. Microspheres were prepared by using ethyl cellulose as a polymer by solvent evaporation method. In this investigation 3full factorial design was used to investigate the joint influence of two variables: the stirring speed (X1), concentration of ethylcellulose (X2), on the time for % of drug release after 12 hours and entrapment efficiency. Potential variables such as stirring time, volume of volatile solvent were kept constant in the experimental design. A statistical model with significant interaction terms is derived to predict the % drug release .The results of F statistics revealed that for obtaining controlled drug release, the microspheres should be prepared using relatively high stirring speed and high concentration of ethylcellulose. The model F values are found to be significant in nature. Response surface plots are presented to show the effect of X1, X2 on the % of drug release and entrapment efficiency. Acceptable batches were identified with the help of experimental design.