V. Srujana, T. Praveen Kumar, P. Narayana Raju, G. Nagarjuna Reddy
The objective of the present research was to formulate clopidogrel bisulphate floating matrix tablets by direct compression method to prolong the gastric residence time and to improve bioavailability of the drug. Various grades of HPMC such as K4M, K15M, K100M, cellulose acetate and Ethyl cellulose N50 were used as drug release retarding polymers and sodium bicarbonate is used as gas generating agent. The formulated tablets were characterized for quality control tests like weight variation, hardness, friability, % drug content, lag time and total floating time. The effect of concentration and viscosity of polymer and combination of different polymers on in vitro drug release was studied including release kinetics, swelling and erosion index. Quality control tests results were found to be uniform within the pharmacopoeial limits. In vitro drug release study showed that formulations containing HPMC K4M extended drug release upto 5hrs to 9 hrs, formulations containing HPMC K15M extended drug release upto 7 hrs to 11 hrs and formulation containing HPMC K100M extended drug release upto 9 hrs to 13 hrs. F9 showed optimum floating time and extended drug release upto 13 hrs. Combination of polymers also yielded better results when compared to the individual polymer. The drug release mechanism was observed to follow zero order kinetics and non Fickian diffusion mechanism. Drug excipient interaction of the prepared formulations was characterized by FTIR and DSC study and confirmed that no interaction was found. Surface topography, texture of the swollen tablet was studied by using SEM study.
