Hydrogels as potential drug-delivery systems: network design and applications

Hydrogels are 3D crosslinked polymer matrices having a colossal tendency to imbibe water and exhibit swelling under physiological conditions without deformation in their hydrophilic network. Hydrogels being biodegradable and biocompatible, gained consideration due to some unique characteristics: responsiveness to external stimuli (pH, temperature) and swelling in aqueous solutions. Hydrogels offer a promising option for various pharmaceutical and biomedical applications, including tissue-specific drug delivery at a predetermined, controlled rate. This article presents a brief review of the recent and fundamental advances to design hydrogels, the swelling and deswelling mechanism, various crosslinking methods and their use as an intelligent carrier in the pharmaceutical field. Recent applications of hydrogels are also briefly discussed and exemplified.