Investigation of Deep Eutectic Solvents and Their Derivatives for Pharmaceutical Applications

Deep eutectic solvent (DES) is a liquid typically formed by mixing two solids, such as a quaternary ammonium salt (QAS) and a hydrogen bond donor (HBD). It was found that the melting point depression can be statistically correlated with the Hansen solubility parameters of the HBD. It was also discovered that DES derivative (DESD) formed by glycolic acid and choline chloride shows a wide range of enhancement on the solubility of selected weakly basic poorly water-soluble drugs. Furthermore, a new ternary DESD based on choline chloride, glycolic acid, and oxalic acid remarkably increased the solubility of itraconazole to 5.36 mg/mL (a 53600-fold increase). Subsequently, DESD containing itraconazole was used as a topical formulation to deliver itraconazole through bovine hoof membranes. Overall, the development of the ternary DESDs has tremendously increased the solubility of itraconazole, and DESD has displayed great potential as a formulation vehicle for transungual drug delivery.M.Sc