Gastroretentive drug delivery systems: current developments in novel system design and evaluation.

The task of achieving efficient delivery of drugs that have poor bioavailability or narrow absorption windows have plagued the pharmaceutically industry for decades. Thus, much research has been dedicated to the development of novel polymeric-based gastroretentive drug delivery technologies that may optimize the bioavailability and subsequent therapeutic efficacy of such drugs. An effective approach of achieving this is through the prolongation of the gastric residence time employing several gastroretentive drug delivery mechanisms such as the use of buoyant systems, high density systems, magnetic systems, mucoadhesive systems, swelling/expanding systems, superporous hydrogels and the inclusion of gastric motility retarding agents with biocompatible polymeric materials. It is known that variations in the gastric physiology such as, gastric pH, and motility exhibit both intra-as well as inter-subject variability demonstrating a significant impact on the gastric retention time and drug delivery behavior. Nevertheless, gastroretentive drug delivery systems have shown promising results. Therefore, in this mini-review, current research and development in this field (i.e. over the last 3-5 years), the polymeric material used for the design of gastroretentive drug delivery systems and techniques employed for the pharmaceutical evaluation of gastroretentive technologies are comprehensively revealed and discussed in an assimilatory manner.