Formulation and In Vitro Evaluation of Mucoadhesive Buccal Tablet of Venlafaxine Hydrochloride

The present study involves the formulation and evaluation of buccal tablets of venlafaxine hydrochloride, an antidepressant drug belongs to class SNRI(serotonin-nonepinephrine reuptake inhibitor)has high first pass metabolism, So buccal drug delivery has been considered an alternative to the oral dosing for compound subjected to degradation in the gastrointestinal tract or to first pass metabolism. An attempt has been made to developed muccoadhesive buccal tablets comprising of drug containing mucoadhesive layers and drug free backing layer ethyl cellulose of to release the drug for extended period of time with reduction in dosing frequency, dose related side effects and improve bioavaibility of drug. Tablets of Venlafaxine Hydrochloride were prepared by direct compression using muccoadhesive polymers Carbopol 934-P and HPMC K4M.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 goat buccal mucosa as model tissue. In order to determine the mode of release, the data was subjected to Krosmeyer and Peppas diffusion model. All the formulations followed Fickian release mechanism. Tablet containing Carbopol 934P and HPMC K4M in the ratio of 1:1(25%) had maximum in vitro drug release for 8 hrs.