Experimental design to predict process variables in the preparation of cellulose based sustained release microspheres system loaded with prednisolone-cyclodextrin complex

The purpose of this study was to evolve experimental design, to prepare the sustained release microspheres loaded with prednisolone-hydroxypropyl-β-cyclodextrin complex, and develop a successful mathematical model to predict various characteristics of microspheres. Response surface methodology (RSM) has been employed to develop model equations that correlate process variables such as ethyl cellulose (EC, mg), hydroxypropyl methyl cellulose (HPMC, mg), stirring speed (rpm) and surfactant (%) with the response variables such as entrapment efficiency (%), particle size (μm) and release rate (%) of the drug. The adequacy of model equations is confirmed by ANOVA result. Results as predicted by model equations are in good agreement with that of experimental results. In vitro drug release shows that drug (93%) is released from a check point formulation (CPF 2) over the period of 24 h with a sustained release fashion with Quasi-Fickian kinetics. Surface morphology of microspheres varies with the experimental conditions as evidenced by scanning electron microscopy.