Formulaqtion and evaluation of gastroretentive drug delivery system using biodegradable polymers

Abstract

Pharmaceutical dosage forms contain both pharmacologically active compounds and excipients added to aid the formulation and manufacture of the subsequent dosage form for administration to patients. Indeed, the properties of the final dosage form (i.e. its bioavailability and stability) are, for the most part, highly dependent on the excipients chosen, their concentration and interaction with both the active compound and each other. No longer can excipients be regarded simply as inert or inactive ingredients, and a detailed knowledge not only of the physical and chemical properties but also of the safety, handling and regulatory status of these materials is essential for formulators throughout the world. In addition, the growth of novel, controlled forms of delivery has resulted in the number of the excipients being used and optimized drug delivery in the sense that the therapeutic efficacy of a drug is optimized which implies nil or minimum side effects. Now a days, oral controlled release systems are designed offering a number of advantages including improvement in patient compliance, therapeutic efficacy and safety, decreased side effects and reduced dosing frequency. Majority of the drugs are having site specific absorption in the G.I. tract and parameters like pH dependent solubility, stability and ionization of the drug in different portions of the G.I. tract, influence such absorption. Gastric Retention Time is one of the important factors, which adversely affect the performance of an oral controlled drug delivery system. Gastric retention systems are such systems, which increase the gastric retention time of the dosage form at the stomach and upper parts of the small intestine and suitable for the drugs having site-specific absorption from the above sites.