Characterization of w/o-type Microemulsions Containing l-Menthol-based Deep Eutectic Solvents for Use in Transdermal Drug Delivery

Abstract We investigated the structural properties of microemulsions (MEs) dispersed in oil base including hydrophobic deep eutectic solvents (DESs) and their skin permeabilities. The results showed that the addition of DESs can improve the skin penetration of monodispersed MEs by disturbing the lipid structures in the stratum corneum. Further addition of DESs caused the structural transition of MEs from a sphere to a cylinder and a bicontinuous system and decreased reduced skin penetration.