Deep Eutectic Solvent (DES)–Based Gels: Structure, Properties, and Emerging Pharmaceutical Applications

Deep eutectic solvents (DES) have emerged as highly versatile, green, and tunable solvents that exhibit remarkable hydrogen-bonding capacity and excellent biocompatibility. When incorporated into polymeric networks, they form DES-based gels—hybrid semi-solid systems that merge the structural integrity of gels with the functional advantages of DES. These materials demonstrate exceptional potential in pharmaceutical sciences by offering improved solubility for poorly soluble drugs, enhanced dermal and mucosal permeation, greater chemical and thermal stability, and more controlled drug-release behaviour compared to conventional hydrogels. Recent advances reveal their promising utility across diverse applications, including topical formulations, wound healing, enzyme stabilisation, nanomedicine, and buccal mucoadhesive delivery. This mini-review summarises the composition, structural features, and mechanisms of action, and therapeutic advantages of DES-gels, while also outlining key challenges and future research opportunities necessary for their translation into safe and clinically relevant systems.