Biomedical applications of hydrogels in drug delivery system: An update

Conventional drug delivery system generally deals with the issues involving repeated dosing and systemic tox-icities. Since few decades, hydrogels have played a significant role as a carrier in drug delivery to minimize the drawbacks pertaining to conventional drug delivery. They. have been considered as one of the most reliable groups of biomaterials due to their biocompatibility, physicochemical properties, and designed interaction with living surroundings. The diversity and versatility of hydrogels make them extraordinary not only in the field of targeted drug delivery but also in tissue engineering, fabrication of contact lenses, and wound dressings. Another reason which makes hydrogels a smart carrier in drug delivery is their special characteristic to retain water inside their network. In recent years, hydrogels fabricated from natural, semi-synthetic, and synthetic polymers have gained a lot of attention in targeted drug delivery of therapeutic agents for the management of cancer, gastric ulcers, brain tumors, diabetes, bacterial infections, etc. Also, with their tremendous capability to modify, hydrogels proved to be a promising vehicle for drug delivery in cosmetological and dermatological conditions. The motive behind this review is to highlight the key concept of hydrogels, their fabrication methods, stimuli-responsive polymers used for their fabrication, and their diverse utilization in the delivery system. Further, different completed and ongoing clinical trials of hydrogel-based drugs have also been discussed. Suitable studies are provided from the literature that supports the tremendous utilization of hydrogels in different segments and how they are modified suitably in several ways to achieve desired targeted delivery of therapeutic agents.