MET Institute of Pharmacy, India
Title: Gastro-retentive drug delivery systems- An Insight
Biography: Abha Doshi
Some of the drugs get absorbed from a particular absorption site in the GI tract i.e., they have absorption window like stomach or upper part of the intestine. These drugs do not get absorbed completely when administered in the form of a typical controlled drug delivery system. Gastro-retentive drug delivery systems (GRDDS) can be used as carriers for drugs with a so-called absorption window. It is obtained by retaining dosage form into stomach and drug is being released at controlled manner to the specific site either in stomach, duodenum or intestine. Several gastro-retentive drug delivery approaches being designed and developed including high density system that is retained in the bottom of the stomach, low density (floating) systems that causes buoyancy in gastric fluid, mucoadhesive systems that causes bioadhesion to stomach mucosa, unfoldable, extendible or swellable systems which limits emptying of the dosage form through the pyloric sphincter of stomach, superporous hydrogel systems and magnetic systems etc. Floating drug delivery systems (FDDS) or hydrodynamically controlled systems are lowdensity systems that have sufficient buoyancy to float over the gastric content and remain buoyant in the stomach without affecting the gastric emptying rate for a prolonged period of time. While the system is floating on the gastric contents, the drug is released slowly at the desired rate from the system. Floating tablets of cinnarizine, losartan potassium, famotidine, and norfloxacin were developed. Superporous hydrogels are swellable systems with a pore size greater than 100 microns. These systems instantly swell in the stomach and maintain their integrity in the harsh stomach environment, while releasing the pharmaceutically active ingredient. Supergel hydrogel composite of Zn Carnosine and Cinnarizine were formulated. They were evaluated for their physicochemical characteristics namely floating lag time, total floating time, etc., swelling index and percent drug release.