A More Relevant Dissolution Method for Evaluation of Floating Drug Delivery System

Introduction A modified release drug delivery system with prolonged residence time in the stomach is of particular interest for drugs: (a) that are locally acting in the stomach, (b) that have an absorption window in the stomach or in the upper part of small intestine, (c) that are unstable in the intestinal or colonic environments, or (d) have low solubility at high pH values. Systems that prolong the gastric residence time can also be used as sustained release devices with a reduced frequency of administration and therefore, can improve patient compliance (1). Approaches to increase gastric residence time include: (a) bioadhesive delivery systems that adhere to mucosal surfaces, (b) delivery systems that increase in size to retard passage through the pylorus, and (c) density-controlled delivery systems, that either float or sink in gastric fluids (2-6). In vitro dissolution testing is generally carried out for quality control purposes and to establish an in vivo in vitro correlation. Traditional in vitro dissolution methods have been shown to be poor predictors of in vivo performance for floating dosage forms (7).The currently used in vitro dissolution methods do not mimic the conditions present in the stomach. Researchers around the world have tried different methods for studying in vitro dissolution for floating drug delivery systems (8,9). However, each of the methods has some limitations. Hence, a modified in-vitro dissolution method was evaluated.