FORMULATION AND EVALUATION OF SUSTAINED RELEASE VALSARTAN BASED ON MATRIX TABLET BY USING HYDROPHILIC POLYMER

Abstract

Valsartan is an angiotensin II receptor antagonist (more commonly called an "ARB", or angiotensin receptor blocker, with particularly high affinity for the type I (AT1) angiotensin receptor. By blocking the action of angiotensin, valsartan dilates blood vessels and reduces blood pressure. It is indicated for treatment of high blood pressure either alone or in combination with hydrochlorothiazides. Controlled release drug delivery systems are developed to modulate the apparent absorption or alter the site of release of drugs, in order to achieve specific clinical objectives that cannot be attained with conventional dosage forms. Unlike sustained release preparations, which is used to retard the release of therapeutic agent and its plasma profile is sustained in duration. Matrix systems fall into category of sustained release oral solid products. In a matrix system, the drug substance is homogeneously mixed into the rate controlling materials and other inactive ingredients as a crystalline, amorphous dispersion. Drug release occurs either by drug diffusion or erosion of the matrix system. Matrix system is widely used due to easy to fabricate in a wide range of sizes and shapes, capability of accommodating both low and high drug loading and active ingredients with a wide range of physical and chemical properties and it is suitable for both non-degradable and degradable systems. The solubility of Valsartan was enhanced by making sustained release matrix tablet. Then formulation was characterized and evaluated by FTIR, drug content, swelling index and in vitro dissolution studies.The present study involved the preparation of sustained release matrix tablet of Valsartan by hydrophilic polymer. The tablets were prepared with both direct compression and wet granulation methods. It was found that wet granulation method facilitated greater efficiency in controlling valsartan release behavior from the matrices. Hence, all further formulations were prepared with wet granulation technique.