Self Correcting Monolithic Floating Matrix Tablets of Dipyridamole: Influence of Formulation Variables

The present investigation describes the influence of content of polyethylene oxide and ratio of lactose to starch 1500 on dipyridamole release from self correcting floating matrix tablets using 3 full factorial design. Tablets were evaluated for in vitro floating ability and drug release study using USP 24 type II apparatus using 0.1 N HCI at 100 rpm and temperature of 37±0.5. Multiple regression analysis and two way analysis of variance followed by Tukey test were performed for dependent variables. All formulations floated within 2 min regardless of factors studied and had total floating time of more than 12 h. It was observed that both the factors had significant influence on all dependent variable studied (P<0.05) except the ratio of lactose to starch 1500 did not significantly contribute for Q 1 (P>0.05). As content of polymer increased the release rate declined with increase in value of diffusion exponent giving anomalous drug release to zero order drug release (P<0.05). It was observed that above a certain threshold level of polymer content further increase did not contribute significantly for percentage drug release. Lactose gave higher drug release with release mechanism towards zero order compared to starch 1500 which gave slower release with release mechanism towards diffusion based. Although both the factors significantly contribute for percentage drug release at different time point, the content of polymer dominated. It was observed that polymer content was a dominant controlling factor for drug release kinetics and it could be controlled by employing various blends of fillers.