Development and characterization of gastroretentive mucoadhesive tablets of venlafaxine hydrochloride

The present study was undertaken with an aim to formulation development and evaluation of gastroretentive mucoadhesive sustained release tablet of Venlafaxine hydrochloride which releases the drug in a sustained manner over a period of 12 hours, by using Carbopol 971P in combination with eudragit RS-PO and ethyl cellulose as a mucoadhesive and release retardant respectively. Preformulation study was done initially and results directed for the further course of formulation. Based on Preformulation studies different batches of Venlafaxine hydrochloride were prepared using Carbopol 971P, Eudragit RS-PO and ethyl cellulose chosen for their different hydrophilic properties to calculate the sustained release properties. Sustained release tablets were prepared by direct compression and were evaluated for bioadhesion time, swelling index and matrix erosion, and in vitro drug release. The tablets of batch F3 and F6 had high swelling behaviors but release of drug is very less. And batch F2 having considerable swelling index and in vitro drug release (99.85%). Batch F2 can be taken as an ideal or optimized formulation of sustained release tablets for 12 hour release as it fulfills all the requirements for sustained release tablet. From the discussion it is concluded that use of carbopol as a release retardant and adhesive polymer is very effective; and also it act as strong release retardant in combination with hydrophobic polymers. Keywords: Gastroretentive; Mucoadhesive; Venlafaxine hydrochloride; Tablet.