Enhanced solubility and improved stability of curcumin in novel water-in-deep eutectic solvent microemulsions

Clinical application of curcumin, a phytochemical with diverse biological activities, are restricted by its low solubility and poor stability. Herein, we report exceptionally high solubility (up to 51 mg/mL under ambient conditions) and significantly improved stability (against sunlight and long-term storage) of curcumin in novel water-in-oil microemulsions formed using a non-ionic surfactant Triton X-100 and a hydrophobic deep eutectic solvent constituted of tetra-n-butylammonium chloride and n-decanoic acid in 1 : 2 mol ratio as the bulk oil phase.