Optimization and Characterizations of Delayed Release Multi- Particulates System of Indomethacin: Screening of Formulations Variables and in Vitro Investigations

E-mail: [email protected] The objectives of the present investigation were: (1) to elucidate the effect of formulation variables e.g., amount of Eudragit RS 100, concentration of Tween 80 and agitation speed on in-vitro release profiles of indomethacin from multiparticulates system, formulated with the combination of ethyl cellulose and Eudragit RS 100 by using a novel quasi emulsion solvent diffusion method; (2) to optimize the formulation variables by response surface methodology (RSM) ; and (3) to characterize the products on the basis of FTIR, thermal , particle size, SEM, X-ray analyses and drug release kinetics studies. Experiments were designed and data was collected according to a three levels face centered central composite design. It was found that in-vitro release (Y1-Y3) were decreased significantly (p<0.05) with increase in amount of Eudragit RS 100 but increased significantly (p<0.05) with increase in surfactant concentration and stirring speed. The analysis of dissolution kinetics data showed that it followed Higuchi and zero-order model rather than first order model. It was observed that the drug release data of the selected formulation was close to the predicted release pattern. Therefore this approach suggested that the combination of Eudragit RS 100 and ethyl cellulose microspheres may be useful for the delivery of maximum amount of indomethacin in intact form to the colon.