This review describes hydrogels and their classifications along with the synthesis and properties of biopolymer-dextrin based crosslinked hydrogels towards potential application in controlled drug delivery.

We report on the synthesis and characterization of a novel hydrogel based on dextrin grafted with poly(2-hydroxyethyl methacrylate) by embedding N,N′-methylene bis acrylamide (MBA) as cross linker, into a polymeric network in the presence of potassium persulphate (KPS) initiator for colon specific delivery of ornidazole. Various grades of hydrogels [Dxt-g-p(HEMA)] have been synthesized by altering the reaction parameters and the best one optimized. The developed hydrogel has been characterized using FTIR spectra, ¹³C NMR spectra, elemental analysis, XRD study, SEM analysis, TGA analysis, swelling study and cell viability study. The equilibrium swelling ratio of the hydrogels has been recorded in different media and found to be at a maximum at pH 7.4. A cell viability study indicates that the hydrogel is non-cytotoxic in nature. The drug delivery results demonstrate that Dxt-g-p(HEMA) delivers ornidazole successfully in the colonic region in a controlled way and is a good candidate for an orally administered drug delivery system. The release mechanism and kinetics of ornidazole from various hydrogels have been determined using different linear and nonlinear mathematical models, which confirm that ornidazole release from hydrogel follows first order kinetics and a non-Fickian diffusion mechanism.