Designer Solvents for Pharmaceutics: Role of Ionic Liquids/ Deep Eutectic Solvents in Pharmaceutical Formulations

The design of biologic and synthetic drugs in the pharmaceutical industry is facing three key challenges, namely, ensuring bioavailability, solubility, and stability. Ionic liquids (ILs) and deep eutectic solvents (DESs), classified as designer solvents, have emerged as excellent solvents for improving the permeability and stability of biotherapeutic drugs. Moreover, they have shown remarkable solubilizing effects for synthetic drugs, particularly in solubilizing active pharmaceutical ingredients (API), and are known as eco‐friendly solvents. Thus, in this review, the development of designer formulations in pharmaceutical industries is reported, and the underlying strategies for designing the most efficient formulations for both biotherapeutics and synthetic drugs are examined. Designer solvents are emerging as novel media in pharmaceutical industries for small and biologics molecules. These solvents are employed in processes ranging from separation to final formulation. This review underscores the impact of designer solvents in pharmaceuticals, focusing on drug‐solvent interactions and their potential applications based on drugs' physical and chemical properties. Further research is encouraged to maximize their utility in pharmaceutical sciences.