Title
Evaluation of cross-linked hydroxypropyl methylcellulose graft-methacrylic acid copolymer as extended release oral drug carrier
Authors
LIAQAT ALI MAHMOOD AHMAD MUHAMMAD USMAN

Received October 4, 2013
Published Volume 49 Issue 2 February
Keywords methacrylic acid, polymer volume fraction, venlafaxine, release profile, absorptivity, cumulative release

Abstract
Here, we synthesized a new smart hydrogel matrix system (HPMC-co-MAc) by graft copolymerization of hydroxypropyl methylcellulose (HPMC) with methacrylic acid (MAc). Methylene bisacrylamide (MBAc) was used as crosslinker and benzoyl peroxide (BPO) as thermal based free radical initiator. The structure and morphology of the new polymer were characterized by FT-IR and SEM, respectively. Absorptivity and diffusion coefficients were calculated to assess drug diffusion behaviour. Drug release behaviour was analyzed at pH 3.0, 5.5 and 7.0. The incorporation of venlafaxine hydrochloride increased with an increasing ratio of HPMC and decreased with an increasing ratio of MBAc. In acidic medium, the drug diffusion rate was limited, while rapid release was observed in neutral/basic medium. Drug release followed zero-order kinetics and the mechanism of release was anomalous diffusion. The dissolution profile of the drug was dependent on the pH of the release media and on copolymer composition. HPMC-co-MAc is a suitable material to be applied in therapeutics for once-daily dosing.