Hydrogels Platforms Addressing the Multiple Applications in Medicinal and Drug Delivery: A Critical Review

Hydrogels are three-dimensional polymeric networks renowned for their remarkable water-absorbing capacity, tunable physicochemical properties, and high biocompatibility. This review comprehensively explores the synthesis, classification, and physicochemical and biological characteristics of both natural and synthetic hydrogels. Advances in crosslinking mechanisms, including ionic, chemical, and physical methods, are critically analyzed alongside their functional properties such as pH-, temperature-, and photo-responsiveness. Special emphasis is given to the role of hydrogels in drug delivery systems, including buccal, oral, vaginal, transdermal, ocular, and injectable formulations. Additionally, their applications in wound healing, tissue engineering, biosensing, and 3D cell cultures are examined. Limitations and challenges in clinical translation, regulatory concerns, scale-up processes, and strategies to enhance drug loading and controlled release are discussed. The review underscores the transformative potential of hydrogels in personalized and regenerative medicine and calls for further translational research to address current constraints and expand clinical applicability.