Swelling, erosion and drug release characteristics of Sodium Diclofenac from heterogeneous matrix tablets

Abstract

The aim of this study was to investigate the effect of combination lipophilic (Acryl-EZE®) and hydrophilic (HPMC) polymers on the release of Sodium Diclofenac (DS) from a tablet. The microgranules were prepared using a fluidized bed followed by direct compression. Swelling and erosion studies of polymer matrix tablets were carried out in various media. The matrix tablets formed a continuous gel layer while in contact with the aqueous medium undergoing a combination of swelling and erosion. The swelling action of matrices was controlled by the rate of its hydration in the medium. The in vitro release was examined with and without rat caecal contents. Release studies showed that the swelling and erosion influenced the drug release. The good fit to Higuchi equation, the n values from Korsmeyer equation and the prevalence of kd over kr in Peppas-Sahlin equation revealed a drug release mechanism controlled mainly by diffusion.