The effect of the ratio of two acrylic polymers on the in vitro release kinetics of ketoprofen from pellets prepared by extrusion and spheronisation technique.

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) & 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 & 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 as 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 & Eudragit RS 30 D. In buffer media, evidence of burst release was observed for the pellets coated with Eudragit RL 30 D & 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 & Eudragit RS and follows Higuchi's release kinetics when ratio was 1:0 & 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.