Ionic liquids: Formulation avenues, drug delivery and therapeutic updates

Numerous challenges are faced during formulation and biopharmaceutics of newly developed drug molecules due to polymorphic conversion, poor bioavailability, stability issues, etc. The condition gets further worsened due to poor solubility or slight solubility of drugs. Thus, the formation of efficient drugs and their incorporation in the delivery system cripples efficient dosage form design. Hence, need has been felt to use novel solvents/devise strategy, which can improve biopharmaceutical performance of drug, take a drug to the molecular level in vivo, that with maintaining biocompatibility, and no toxicity. Ionic liquids seem to be a promising solvent for drugs having poor solubility and bioavailability. The facile synthesis, tunable physico-chemical and biological properties, make them unique in drug delivery systems. As conventional ILs are non-biodegradable and may be toxic, the emergence of bio-ionic liquids (B-ILs) needs pitching. Being bio-friendly with a multitude of applications in the drug delivery and health care area makes them prospective excipients for pharmaceutical formulations. By virtue of their non-volatile, biocompatible and nontoxic nature, B-ILs liquids can have limitless applications as a substitute for both, conventional ILs, and organic-inorganic solvents. The ILs and B-ILs may be used as solubility enhancers, permeability enhancers, drug-ILs, protein stabilizers, etc. The prominent role of B-ILs in different drug delivery systems viz: oral, transdermal, and topical has been delineated in the last decade. This review emphasizes types of ionic liquids, B-ILs, customization avenues, formulation avenues, drug delivery applications, cancer diagnostics and therapeutics.