FORMULATION AND EVALUATION OF VENLAFAXINE HYDROCHLORIDE MUCOADHESIVE BUCCAL TABLETS

Abstract

The present study involves the formulation and evaluation of buccal tablets of venlafaxine hydrochloride, an antidepressant drug to circumvent the first pass metabolism. Buccal route is excellent for the systemic delivery, there by rendering great bioavailability. A significant reduction in dose and dosing frequency can be achieved, thereby reducing dose dependent side effects, patient compliance and prolonging duration of action. Tablets of venlafaxine HCl were prepared by direct compression method. Twelve formulations were prepared with varying concentrations of bioadhesive polymers like hydroxypropylmethylcellulose K4M (HPMC K4M), carboxymethylcellulose (CMC), carbopol 934P and chitosan. Buccal tablets were evaluated by different parameters such as thickness, hardness, weight uniformity, content uniformity, swelling index, surface pH, ex vivo bioadhesive strength, in vitro drug release, ex vivo drug permeation and FTIR studies. The modified in vitro assembly was used to measure the bioadhesive strength of tablets with fresh porcine buccal mucosa as model tissue. The tablets were evaluated for in vitro release in pH 6.8 phosphate buffer for 8 hours in standard dissolution apparatus in order to determine the mode of release, the data was subjected to model fitting, the optimized formula followed non-fickian release mechanism with zero order kinetics. The formulation containing venlafaxine HCl and HPMC K4M in the ratio of 1:1 could be used to design effective and stable buccoadhesive tablets of venlafaxine HCl.