Development and Evaluation of Oral controlled release formulations for Antianginal and Antihypertensive Drugs

Abstract

Oral route is the most common and preferred route for the delivery of most therapeutic agents due to its ease of administration, patient compliance and cost effective manufacturing methods. Oral controlled drug delivery systems have received much attention of the researchers during the past two decades. The rationale for developing a controlled release formulation is to enhance its therapeutic benefits reducing its side effects and improving the management of diseased condition. A number of strategies have been developed to obtain controlled release of the drug in the body. These include a simple matrix tablet to more technologically sophisticated products which are introduced to the market place. Studies have been carried out for developing oral controlled release matrix tablet formulations of verapamil hydrochloride and losartan potassium by using polymeric materials like polyox WSR 301 polyox WSR 303 polymethacrylates ethylcellulose xanthan gum, guar gum karaya gum and sodium alginate. These are selected as matrix forming polymers for controlled release as these were reported to have matrix forming property. Studies were conducted to investigate the influence of poly level and type on the controlled release of the drugs from matrix tablets by in vitro methods. The influence of nature of fillers in the matrix tablets on drug release rate and mechanism was studied. viii Studies were under taken to evaluate the influence of binary polymeric systems on the controlled release of the drugs from the matrix tablets. For this purpose a combination of hydrophilic polymer like poly with hydrophobic polymers like methacrylates and ethyl cellulose were used in the matrix tablets. A combination of synthetic and natural polymers like poly and various natural gums were also used in the matrix tablets to study their influence on controlling the drug release.