Formulation Design and in Vitro Evaluation Studies of Antidepressant Venlafaxine Hydrochloride Oral Drug Delivery Systems

Abstract

Background: Venlafaxine Hydrochloride a serotonin, nor epinephrine reuptake inhibitor, oral antidepressant used to treat depression.

Objective: The present study was aimed at studying controlled release of Venlafaxine Hydrochloride with Guargum, Hydroxy propyl methyl cellulose as matrix polymers, Micro crystalline cellulose as binder and Dicalcium phosphate as diluent filler.

Methods: Tablets were studied for pre, post compression, swelling and in vitro dissolution studies. Drug release was analyzed by release kinetic models.

Results: Preformulation studies revealed that the drug procured was pure. Analytical method was linear and precise. The rheological parameters were within the ideal limits and suitable for compression. Swelling index increased with increase in matrix polymer content. In vitro studies showed drug release, sustained for 18 to 24 h. Optimized formulation V5 released 14.32±0.430% in 2 h. At the end of 12 and 24 h it has released 49.37±0.685% and 98.31±0.435% of drug respectively and followed peppa’s kinetics with anomalous (Non fickian) diffusion mechanism of drug release.

Discussion: The drug release from swollen gel matrix occurred initially by drug diffusion followed by polymer chain relaxation and erosion. The in vitro release kinetics from majority of formulations followed Peppa’s and zero order kinetics. The peppa’s n values indicated drug release via anomalous (non fickian) diffusion and super case II transport.

Conclusion: Venlafaxine HCl release form tablets sustained up to 24 h which could provide better bioavailability and improved patient compliance.

Keywords: Venlafaxine HCl, controlled release matrix tablets, guar gum, Hydroxy propyl methyl cellulose, In vitro studies, Release kinetics.