DESIGN AND EVALUATION OF INTRAGASTRIC BUOYANT TABLETS OF VENLAFAXINE HYDROCHLORIDE

Objective: The present study was undertaken to prolong the release of orally administered drug. The aim is to formulate, develop, and evaluate theintragastric buoyant tablets of venlafaxine hydrochloride, which releases the drug in a sustained manner over a period of 12 hrs. Different formulationswere formulated using the polymers Carbopol 934 P, xanthan gum, hydroxypropyl methylcellulose (HPMC K100M) with varying concentration ofdrug: Polymer ratio of 1:1, 1:1.5, 1:2, in which sodium bicarbonate acts as gas generating agent, and microcrystalline cellulose as a diluent.Methods: The tablets were prepared by direct compression and evaluated for tablet thickness, weight variation, tablet hardness, friability, in vitrobuoyancy test, in vitro drug release and Fourier transform infrared spectroscopy. Formulations were evaluated by floating time, floating lag time and in vitro drug release. Dissolution profiles were subjected for various kinetic treatments to analyze the release pattern of drug.Results: It was found that drug release depends on swelling, erosion, and diffusion, thus following the non-Fickian/anomalous type of diffusion.Formulation F8 was considered as an optimized formulation for gastro retentive floating tablet of venlafaxine hydrochloride. The optimizedformulation showed sustained drug release and remained buoyant on the surface of the medium for more than 12 hrs. As the concentration of HPMCK100M increases in the formulation the drug release rate was found to be decreased. The optimized formulation was subjected for the stability studiesand was found to be stable as no significant change was observed in various evaluated parameters of the formulation.Conclusion: It can be concluded that floating drug delivery system of venlafaxine hydrochloride can be successfully formulated as an approach toincrease gastric residence time, thereby improving its bioavailability. Â