Floating systems

Over the years, oral dosage forms have become increasingly sophisticated with major role being played by control release drug delivery system. CRDDS release drug at a predetermined rate, as determined by drug’s pharmacokinetics and desired therapeutic concentration. This help in achieving predictable drug plasma concentration required for therapeutic effect. Gastroretentive drug delivery is an approach to prolong gastric residence time, thereby targeting site-specific drug release in the upper gastrointestinal tract (GIT) for local or systemic effects. Gastroretentive dosage forms can remain in the gastric region for long periods and hence significantly prolong the gastric retention time (GRT) of drugs. Over the last few decades, several gastroretentive drug delivery approaches being designed and developed, including: high density (sinking) systems that is retained in the bottom of the stomach, low density (floating) systems that causes buoyancy in gastric fluid, mucooadhesive systems that causes bioadhesion to stomach mucosa , unfold able, extendible, or swellable systems which limits emptying of the dosage forms through the pyloric sphincter of stomach, superporous hydrogel systems , magnetic systems etc.