Recent developments in superporous hydrogels.

Superporous hydrogels (SPHs) were originally developed as a novel drug delivery system to retain drugs in the gastric medium. These systems should instantly swell in the stomach and maintain their integrity in the harsh stomach environment, while releasing the pharmaceutical active ingredient. For years, the synthetic features and properties of these SPH materials have been modified and improved to meet the requirements for gastric retention applications. Furthermore, an instant swelling hydrogel has also shown potential application for peroral intestinal peptide and protein absorption. This review discusses the formulation, characterization, properties and applications of these polymers.