Hydrogels, characterized by their three-dimensional networks of hydrophilic polymers, have emerged as a cornerstone in biomedical applications, including drug delivery, tissue engineering, and wound healing. This review delves into the classification of hydrogels based on cross-linking methods, providing insights into their synthesis, properties, and applications. Recent advancements in hydrogel-based drug delivery systems, including oral, injectable, topical, and ocular approaches, are highlighted, emphasizing their significance in enhancing therapeutic outcomes. Challenges in clinical translation and future directions for personalized medicine and regenerative healthcare solutions are also discussed. The review underscores the transformative potential of hydrogels in biomedical engineering, highlighting their evolving applications and the need for ongoing innovation to address existing challenges.Hydrogels, characterized by their three-dimensional networks of hydrophilic polymers, have emerged as a cornerstone in biomedical applications, including drug delivery, tissue engineering, and wound healing. This review delves into the classification of hydrogels based on cross-linking methods, providing insights into their synthesis, properties, and applications. Recent advancements in hydrogel-based drug delivery systems, including oral, injectable, topical, and ocular approaches, are highlighted, emphasizing their significance in enhancing therapeutic outcomes. Challenges in clinical translation and future directions for personalized medicine and regenerative healthcare solutions are also discussed. The review underscores the transformative potential of hydrogels in biomedical engineering, highlighting their evolving applications and the need for ongoing innovation to address existing challenges.