Hydrogel: Polymeric Smart Material in Drug Delivery

Abstract

A ‘biomaterial’, recognizes some materials for biomedical applications like replacement of living system and wound stressing. ‘Biomaterials’ includes different compounds from diverse origins, like polymers, metals, ceramics and composites. Along with conventional natural polymers (polysaccharides, proteins), synthetic and biodegradable polymers like Polyvinyl alcohol, Polyvinylpyrrolidone, Polyetheleneglycol, Polylactic acid, Polyhydroxy acid are promisingly used in drug delivery, tissue engineering, biomedical sensing, skin grafting and medical adhesives. ‘Hydrogel’ a new generation biodegradable polymer typically used for pharmaceutical and medical purposes. Hydrogels are coined as super absorbent with significant function in health care, especially in wound treatment and protection. Unique characteristics features like enhanced hydrophilicity, biocompatibility, zero-toxicity and biodegradability along with soft and rubbery consistency, low interfacial tension and ‘self-healing’ properties make them compatible with living tissues. Hydrogels have been widely investigated as the carrier for drug delivery systems owing to their unusual characteristics like swelling in aqueous medium, pH and temperature sensitivity, or sensitivity towards other stimuli. Hydrogels being biocompatible materials have been recognized to function as drug protectors, especially for peptides and proteins, from in-vivo environment. In present context, development of ‘in situ’ forming systems for various biomedical applications, including drug delivery, cell encapsulation, and tissue repair are emerging. Among several typical hydrogel synthesis approaches like, solvent exchange, UV-irradiation, ionic cross-linkage, pH change, and temperature modulation, the ‘thermosensitive’ approach is advantageous since it does not require use of any organic solvents, co-polymerization agents and externally applied trigger for gelation. This review presents an overview to the advances in hydrogel based drug delivery system with some reconstructive features in the biomedical applications.