Ionic
liquids (ILs) are a class of nonmolecular compounds composed
only of ions. Compared with traditional organic solvents, ILs have
the advantages of wide chemical space, diverse and flexible structures,
negligible vapor pressure, and high thermal stability, which make
them widely used in many fields of modern science, such as chemical
synthesis and catalytic decomposition, electrochemistry, biomass conversion,
and biotransformation biotechnology. Because of their special characteristics,
ILs have been favored in the pharmaceutical field recently, especially
for the development of efficient drug delivery systems. So far, ILs
have been successfully designed to promote the dissolution of poorly
soluble drugs and the destruction of physiological barriers, such
as the tight junction between the stratum corneum and the intestinal
epithelium. In addition, ILs can also be combined with other drug
strategies to stabilize the structure of small molecules. This Review
mainly introduces the application of ILs in drug delivery, emphasizes
the potential mechanism of ILs, and presents the key research directions
of ILs in the future.