Rate Controlled Release of Naproxen from HPMC Based Sustained Release Dosage Form: I. Microcapsule Compressed Tablet and Matrices

Abstract

The aim of the present study was to investigate the release kinetic profiles of Naproxen (NP) from microcapsule compressed as well as matrix tablets using a combination of water insoluble materials with hydrophilic polymers. The ethyl cellulose (EC)/ hydroxy propyl methyl cellulose (HPMC) combination controlled the release rate of NP by their concentration ratios from the microcapsule compressed tablets. When the hydrophilic part of the combination was increased, the release rate of NP was rationally increased. Accordingly their kinetic constants as well as diffusion coefficients also increased. It can be concluded that the hydrophilic part HPMC could contribute a developed-macromolecular network structure along with EC, through which the NP release can be controlled like twining-release system. On the other hand introduction of waxy materials like bees wax (BW), cetyl alcohol (CA) and stearic acid (SA) into the HPMC based matrices showed a different release pattern. In this case increased hydrophobic part of the combinations decreased the release profiles including kinetic constant as well as diffusion coefficient. The first 60% kinetic profiles showed that tablets using all the additives released the drug by a non-Fickian diffusion (approx. zero order Model). Key words: Sustained release, Microcapsule, Naproxen, Diffusion exponent, Kinetic constant, Diffusion coefficient Dhaka Univ. J. Pharm. Sci. Vol.4(1) 2005 The full text is of this article is available at the Dhaka Univ. J. Pharm. Sci. website