Microspheres as floating drug-delivery systems to increase gastric retention of drugs

Gastric emptying is a complex process, which is highly variable and makes i n vivo performance of the drug-delivery systems uncertain. In order to avoi d this variability, efforts have been made to increase the retention time o f the drug-delivery systems for more than 12 h. The floating or hydrodynami cally controlled drug-delivery systems are useful in such applications. The present review addresses briefly the physiology of the gastric emptying pr ocess with respect to floating drug-delivery systems. In recent years, the multiparticulate drug-delivery systems are used in the oral delivery of dru gs. One of the approaches toward this goal is to develop the floating micro spheres so as to increase the gastric retention time. Such systems have mor e advantages over the single-unit dosage forms. The development of floating microspheres involves different solvent evaporation techniques to create t he hollow inner core. The present review addresses the preparation and char acterization of the floating microspheres for the peroral route of administ ration of the drug.