Design development and evaluation of bi-layered tablet of Divalproex sodium

Abstract

Divalproex sodium is considered as the most important antiepileptic drug and widely used for treatment of epilepsy
and bi-polar disorders and prophylaxis of migraine. The formulation of bi-layered tablet of Divalproex sodium
containing immediate release layer and sustained release layer by HPMC K4M and HPMC K100M polymer used to
retard the drug release from sustained release layer in different proportion and combination and evaluated for
physical parameter along with in vitro drug release studies.. In vitro drug release studies were performed using USP
type II apparatus (paddle method) in 900 ml of phosphate buffer pH 6.8 at 100 rpm.. The FTIR study revealed that
there was no interaction between drug and polymer and combination can be safely prepared. Both layers were
prepared by wet granulation technique as poor flow property exhibited by pure drug. The immediate release layer
was formulated by using sodium starch glycolate, croscarmellose sodium as superdisintegrants and evaluated for
physical parameters, disintegration time and in vitro drug release. The optimized immediate release layer (IF6) with
highest in vitro release of 98.11 was selected for bi-layered tablet formulation. Finally Bi-layered tablets were
prepared by double compression of selected sustained release layer and immediate release layer of Divalproex
sodium.