Formulation and evaluation of Floating Drug Delivery Systems for some selected drugs

Abstract

The purpose of this investigation was to develop a controlled release floating drug delivery system (tablets and hollow microspheres) of Losartan potassium, Verapamil hydrochloride and Rosiglitazone maleate. The aim of the first study was to develop and evaluate non-effervescent floating matrix tablets. Drugs having narrow absorption window and those which are absorbed mainly in stomach were developed as floating delivery system. Losartan potassium, a class I anti-hypertensive agent, is well absorbed in stomach and upper part of small intestine. Hence there is need to develop floating dosage form. Floating matrix tablets were prepared by direct compression method employing polypropylene foam powder (Accurel® MP 1000), Karaya gum and Chitosan. Tablets were characterized by FT-IR, DSC studies and evaluated for floating lag time, duration of buoyancy, friability, hardness, thickness, weight variation, swelling studies, drug content, in vitro drug release studies and in vivo studies. FT- IR and DSC studies showed that there is no interaction between the drug and excipients. The tablets showed zero floating lag time and remained buoyant for more than 12 h achieving the gastric retention properties. All evaluation parameters were within the Pharmacopoeial limits. The in vitro drug release was sustained up to 12 h and release rates were fitted into an empirical equation to compute the diffusion parameter which indicates a super case II- transport mechanism. X-ray photographs confirm presence of tablet in rabbit stomach for more than 12 h. The studies concluded that floating matrix tablets could be used as floating drug delivery systems in view of their floatation in stomach.