Design, development and evaluation of clopidogrel bisulfate fl oating tablets

Objective: The objective of the present work was to formulate and to characterize a fl oating drug delivery system for clopidogrel bisulphate to improve bioavailability and to minimize the side effects of the drug such as gastric bleeding and drug resistance development. Materials and Methods: Clopidogrel fl oating tablets were prepared by direct compression technique by the use of three polymers xanthan gum, hydroxypropyl methylcellulose (HPMC) K15M and HPMC K4M in different concentrations (20%, 25% and 30% w/w). Sodium bicarbonate (15% w/w) and microcrystalline cellulose (30% w/w) were used as gas generating agent and diluent respectively. Studies were carried out on fl oating behavior and infl uence of type of polymer on drug release rate. All the formulations were subjected to various quality control and in-vitro dissolution studies in 0.1 N hydrochloric acid (1.2 pH) and corresponding dissolution data were fi tted to popular release kinetic equations in order to evaluate release mechanisms and kinetics. Results and Discussion: All the clopidogrel fl oating formulations followed fi rst order kinetics, Higuchi drug release kinetics with diffusion as the dominant mechanism of drug release. As per Korsmeyer-Peppas equation, the release exponent “n” ranged 0.452-0.654 indicating that drug release from all the formulations was by non-Fickian diffusion mechanism. The drug release rate of clopidogrel was found to be affected by the type and concentration of the polymer used in the formulation (P < 0.05). As the concentration of the polymer was increased, the drug release was found to be retarded. Conclusion: Based on the results, clopidogrel fl oating tablets prepared by employing xanthan gum at concentration 25% w/w (formulation F2) was the best formulation with desired in-vitro fl oating time and drug dissolution.