Abstract
Ionic liquids, which are liquid salts at room temperature, attract attention as alternative solvents instead of water and organic solvents. Ionic liquids are composed of organic cation and organic/inorganic anion, and are tuned by combining with various species of ion to obtain desirable characteristics. Application of ionic liquids is currently increasing in medical fields because ionic liquids can increase solubility, stability, and absorption of drugs. Transdermal administration with drugs is non-invasive and convenient approach, while barrier function of the skin limits the absorption of drugs except for hydrophobic small molecular drugs. It has recently reported that the combination of ionic liquids with drugs enables skin permeation of drugs even if the drugs were hydrophilic macromolecules. This suggests that ionic liquids make it possible to treat various types of local and systemic diseases with various drugs, which have never absorbed through the skin barrier. In this review, we introduce the characteristics of ionic liquids used in transdermal drug delivery and application for the several diseases.
