Improving the Solubility of Pharmaceutical Active Ingredients using Biocompatible Ionic Liquids Composed of Choline and/or Amino Acids

Abstract

Ionic liquids (ILs) have emerged as alternative solvents with unique solubilization abilities distinct from those of water and conventional organic solvents. However, most ILs were not originally developed for biological applications, leading to concerns about their toxicity and safety. To overcome these limitations, biocompatible ionic liquids (Biocompatible ILs) composed of naturally derived components such as choline and amino acids have recently attracted considerable interest in pharmaceutical field. This review summarizes recent advances in Biocompatible ILs, including choline–geranate (CAGE), amino acid–fatty acid ILs, and choline–amino acid ILs, with a focus on their ability to enhance the solubility of poorly water-soluble active pharmaceutical ingredients (APIs) and the mechanisms underlying solubilization. Such Biocompatible ILs hold promise for improving the oral absorption, skin permeability, and overall bioavailability of APIs.

graphical abstract