Indian Journal of Novel Drug Delivery 5(4), Oct-Dec, 2013, 187-197 187 Indian Journal of Novel Drug Delivery IJNDD An Official Publication of Karnataka Education and Scientific Society Research Article Formulation and In-vitro Evaluation of Sustained Release Diclofenac Sodium Matrix Tablets using Blends of Cashew Gum, Xanthan Gum and Hydroxypropylmethylcellulose as Hydrophilic Drug Release Modifiers K. OFORI-KWAKYE*, E. OBESE, M. E. BOAKYE-GYASI Department of Pharmaceutics, Faculty of Pharmacy and Pharmaceutical Sciences, College of Health Sciences, Kwame Nkrumah University of Science and Technology (KNUST), Kumasi, Ghana A R T I C L E D E T A I L S A B S T R A C T Article history: Received on 18 October 2013 Modified on 25 November 2013 Accepted on 04 December 2013 Sustained release diclofenac sodium matrix tablets (~100 mg) were prepared by wet granulation using blends of cashew gum, xanthan gum and HPMC as drug release modifiers. The flow properties of diclofenac sodium granules and the physical properties of the compressed matrix tablets namely, weight variation, tablet thickness, crushing strength, friability, drug content and swelling index were evaluated. In vitro dissolution studies were performed in phosphate buffer (pH 7.5) using Voltaren Retard ® tablet as a reference drug. Kinetic models and difference (f1) and similarity (f2) factors were employed to evaluate the drug release data. The granules exhibited good flow properties while the physical properties of tablets generally fell within acceptable limits. Tablet formulations containing 60-100 % xanthan gum exhibited high water absorption capacities in phosphate buffer pH 7.5. Formulations F10, F12, F13 and F15 passed the dissolution test for modified release oral tablets while the rest failed the test. Formulations F7 to F15 appeared similar to the reference drug (p < 0.05; f1 ≤ 10; f2 ≥ 60) and could be used interchangeably. Drug release data fitted well to the Higuchi square root model and the Korsmeyer-Peppas equation, indicating anomalous or non-Fickian drug release. Blends of cashew gum, xanthan gum and HPMC when employed in the appropriate ratios could optimize the sustained release activity of diclofenac sodium matrix tablets. © KESS All rights reserved Keywords: Natural gums, Hydrophilic polymers, Swelling capacity, In vitro dissolution, Sustained release INTRODUCTION Matrix tablets as monolithic systems have been designed by various researchers as sustained release drug delivery systems for oral administration [1-7] . Other techniques which can be used in the design of oral sustained release products include the coating of beads, granules and tablets with polymer materials; complex formation; microencapsulation; and extrusion/spheronization. Matrix drug delivery systems may be produced using both hydrophilic (e. g. HPMC, xanthan gum, sodium alginate) and hydrophobic polymers (e. g. ethylcellulose, polyvinyl chloride) and may be divided into lipid matrix systems, inert or insoluble matrix systems and hydrophilic matrix systems or swellable- soluble systems. Hydrophilic matrix tablets may be produced by direct compression of the mixture of drug and hydrophilic carriers [8] , or from a wet granulation containing the drug and hydrophilic polymer materials. Cashew gum, xanthan gum and HPMC are hydrophilic polymers which are used in matrix tablet formulations as drug release modifiers for controlled drug delivery [9-12] . Cashew gum is obtained as exudates from the stem bark of the tree Anacardium occidentale L. (family: Anacardiaceae). It is naturally-occurring, generally non-toxic, biocompatible and readily available in many tropical and sub-tropical countries. Cashew gum is a complex polysaccharide of high molecular mass which upon hydrolysis yields galactose and galacturonic acid. Cashew gum has been utilized as agglutinant for capsules and pills in the pharmaceutical industry and in the food industry as a stabilizer of juices. The binder and drug *Author for Correspondence: Email: koforikwakye@yahoo.com