EVOLUTION OF HYDROGEL POLYMERS AS CONTACT-LENSES, SURFACE-COATINGS, DRESSINGS, AND DRUG-DELIVERY SYSTEMS

Hydrogel polymers are hydrophilic resins that display excellent biocom patibility, which has allowed their application in diverse fields of s urgery and medicine. The original hydrogel polymer, a copolymer of 2-h ydroxyethyl methacrylate and ethylene dimethacrylate, was developed by Wichterle and Lim in 1954. The development of the first soft hydrogel contact lenses by Wichterle in 1961 represented the first successful clinical application of hydrogel polymers and remains one of the most important uses of hydrogels today. The biocompatibility of hydrogel po lymers may be adapted to diverse tissue types by small variations in t he makeup of the polymer, including varying the type and amount of mon omers and differing the amounts and characteristics of the cross-linki ng agents used to create the polymer chains. Hydrogels have been succe ssfully developed for use as coatings, soft contact lenses, wound dres sings, and drug delivery systems.