Formulation and evaluation of bi-layered tablet of divalproex sodium

Abstract

The formulation known as bi-layered tablet was developed with the aim to deliver the Divalproex sodium as immediate release and extent the drug release for 18 hours for the better and extended clinical effect. Six formulations (IF1-IF6) of immediate release tablets were prepared by using sodium starch glycolate and cross carmellose sodium. Nine formulations (SF1-SF9) of sustained release were prepared by using HPMC K4M and HPMC K100M in different ration and combination.  Bi-layered   tablets   were   prepared   by   using   selected    best formulations of each layer. IF6 from immediate release layer as they showed 98.62 % drug release within 20 minutes. SF8 from sustained release layer as they showed 94.29 % drug release at 18 hours and also the release pattern was within the limit of sustained release tablet. Prepared bi-layered tablet were evaluated for post-compression paramaters. Drug excipient interaction was determined by FTIR. Short term stability studies of formulated bi-layered tablet were carried out at 40^oC/75% RH for 3 months. Stability studies at 40^oC/ 75% RH for 3 months for bi-layered tablet  batches indicated that there are no significant loss in drug content, release profile and physical appearance.