RESUMEN
The aim of this study was to investigate the effect of physico-chemical properties of the polymers on the release profile of ketoprofen from the pellets dosage form. Ammonio Methacrylate Copolymer Type A [Eudragit RL 30 D] and Ammonio Methacrylate Copolymer Type B [Eudragit RS 30 D] were used as release rate retarding polymers. The drug containing core pellets were prepared by extrusion spheronisation technique and subsequently coated with 15% [w/w] polymer load of the combination of Eudragit RL 30 D and Eudragit RS 30 D having ratio 1:0, 4:1, 3:2, 1:1, 2:3, 1:4, 0:1 respectively. Significant differences were found among the drug release profile from different formulations. It was revealed that Eudragit RL 30 D has the effect to increase the initial drug release more significantly where as Eudragit RS 30 D has the effect to minimize the initial drug release but increase the terminal drug release more significantly. In acid media about 50% drug was released from pellets coated only with Eudragit RL 30 D where was only 5% drug was released in case of Eudragit RS 30 D but maximum 10% drug was released from pellets when coated with the combination of Eudragit RL 30 D and Eudragit RS 30 D. In buffer media, evidence of burst release was observed for the pellets coated with Eudragit RL 30 D and Eudragit RS 30 D having ratio of 1:0, 4:1, 3:2 respectively. It was also observed that drug release increases sharply as well as the release best fit to the zero order release kinetics when pellets coated with 1:1 ratio of Eudragit RL 30 D and Eudragit RS and follows Higuchi's release kinetics when ratio was 1:0 and 3:2. The results generated in this study showed that proper selection of polymeric materials based on their physico-chemical properties is important in designing sustained release pellets dosage form with suitable dissolution profile