FORMULATION DEVELOPMENT AND EVALUATION OF CLOPIDOGREL BISULFATE TRANSDERMAL PATCHES

Clopidogrel bisulphate is a drug used in inhibiting the platelet aggregation and also used in the treatment of cardiovascular disorders. It acts by inhibiting the adenosine diphosphate and is almost absorbed (98%) after oral administration. Approximately 50 % of drug is excreted in urine and 40% in feces. The plasma half life of drug is about 8 hours which makes frequent dosing necessary to maintain the therapeutic blood levels of drug for a long term treatment. So the transdermal patches were used to deliver the drug directly to systemic circulation through skin. The transdermal patches were prepared by solvent evaporation method. The influence of varying the combination of polymer concentrations at different ratio was evaluated. The polymers used in this study did not alter physicochemical properties of the drug. All the batches were evaluated for physical appearance, thickness, weight variation and drug content uniformity. The in-vitro drug dissolution study was carried out using Franz diffusion apparatus and the release mechanisms were explored. Mean dissolution time is used to characterize drug release rate from transdermal patch and indicates the drug release retarding efficiency of polymer. The time taken for 92 % of drug release was found to be within 16 hours with F4 formulation while all other formulations were showing 85% drug release for 10 hrs and hence the concentration of PVP and ethyl cellulose 200 mg was best. Hence the optimized formulation was found F4. All the prepared patches exhibited zero order release kinetics, governed by a diffusion mechanism.