Formulation and evaluation of gastro-retentive drug delivery system of losar-tan potassium by using raft-forming approach

Losartan potassium is angiotensin type-II receptor antagonist, used for the treatment anti hypertension. The purpose of this investigation is to improve bioavailability, gastro residence time and to reduce frequency of administration by preparing a gastro-retentive drug delivery system by using raft-forming technique. Losartan potassium was prepared by direct compression method by using various polymers such as HPMC K4M, xanthan gum and carbopol 971p at various concentrations. Sodium bicarbonate and sodium alginate were incorporated as gas generating agents and foaming agents. Lubricating agent like talc and magnesium stearate, lactose as sweetening agent, and microcrystalline cellulose as binding agent, FTIR spectroscopy study reveals that no interaction between drug and polymers. F1-F12 formulations were developed, and evaluated for thickness, weight variation, friability, drug content, floating time, lag time and in-vitro drug release. The in-vitro cumulative % drug release of all formulation ranged from 94.28% to 98.88% at 12hr. the floating time and lag time for the optimized formulation F9 was found to be 20min and 12hrs respectively. In-vitro drug released was found to be 98.88% for F9 at the end of 12hrs and which was considered as best formulation.