Design and evaluation of sustained release tablets of divalproex sodium

Abstract

Epilepsy is abnormal, high frequency electrical discharge in brain characterized by transient episode (seizure) with or without loss of consciousness and characteristic body movement (convulsion). Among many drug of antiepileptic drug, Divalproex sodium is considered as the most important antiepileptic drug and widely used for treatment of epilepsy. The present work has been done to formulate sustained release tablets of divalproex sodium containing HPMC K4M and HPMC K100M as release retarding agent. The FTIR study revealed that there was no interaction between drug and polymer and combination can be safely prepared. The tablets were prepared by wet granulation technique using PVP K30 solution as binding agent. Tablets were evaluated for hardness, thickness, weight variation, disintegration time, drug content and in vitro drug release. All the physical parameters were in acceptable limit of pharmacopeial specification. The in vitro release of sustained release tablet was carried out for 18 hours using USP type-II apparatus (DS-1800) at 100 rpm for the first 45 minute in 900 ml 0.1N HCL maintaining at 37 ± 0.5⁰C and then at phosphate buffer pH 6.8 in 900ml for another 18 hour. The optimized formulation (F8) was found to exhibit more than 90% after 18 hours. Further the drug release of sustained release tablets was compared with the conventional tablet which was prepared by using 5% micro crystalline cellulose (MCC) as disintegrating agent. The stability studies, shown the optimized tablets of immediate release formulation were stable at 40⁰C / 75% RH for a period of 3 months.