Supramolecular Hydrophobic Eutectogels Based on Menthol-Thymol as Thermo- and pH-Responsive Drug Delivery Systems

Supramolecular eutectogels are an emerging class of materials consisting of deep eutectic solvents (DESs) confined in a semisolid 3D network by polymers or a gelation process. These soft materials have applications in many areas, due to the dynamic nature of noncovalent interactions that form the gel network, which makes them stimuli-responsive systems. Herein, we report the preparation and characterization of hydrophobic eutectogels, obtained by gelling nonionic type V DESs, as controlled drug delivery systems. The supramolecular interactions between the DES components thymol-menthol and ethosuximide drug molecules, responsible for the gel structure and dynamics of the small molecules, are investigated by IR, NMR spectroscopy and rheology. In vitro release profiles, explored in different pH and temperature conditions, demonstrated the ability of eutectogel formulations to deliver ethosuximide for up to 3 weeks with a dual thermo/pH responsiveness via diffusion mechanism.