Characterisation and Properties of Third Generation Ionic Liquids

Introducing biological and pharmaceutical perspectives into ionic liquids leads to the formation of a third generation of ionic liquids with lower toxicity and high biodegradability. These 3rd generation ionic liquids overcome the limitations of low thermal stability, solubility, and aggregation often associated with pharmaceutics. In this milieu, the 3rd generation of ionic liquids provides tailor-made biological properties in addition to the conventional ionic liquids (ILs) properties. This chapter provides a concise overview of the basic characterization and a discussion on the extraordinary physicochemical properties of the third generation of ILs/active pharmaceutical ingredients (API)-based ILs in this field. This paper strategically addresses the tuning of molecules to get the desired properties, thermal behavior to determine the transitional of the solid biological component into the liquid, and polymorphism in the field of pharmaceutics. An in-depth view of the nano-structuring phenomena, revealing the insights from structural characterization by NMR and EPR spectroscopy, and also a theoretical understanding of ILs using computational techniques have been discussed. Also, this chapter fosters the understanding of the solubility profiles and surface activity of API-ILs in water to overcome the inadequate biopharmaceutical properties with reference to parent API. This chapter highlights their enhanced biological properties such as antimicrobial, pharmacokinetics, antibacterial activity, etc., and the various literature available on the different API-ILs. This will also include the biomedical perspective, for transport and toxicity studies. The effect of various anions and cations on the various biological and physiochemical properties will be discussed. Overall, the chapter aims to create a comprehensive understanding of the properties and characterization of 3rd generation ILs to pave the way for diverse biological and chemical applications. 

Keywords: Antimicrobial activity, Antibacterial properties, API ionic liquids, Biological applications, Characterization, Green solvent, Low melting point, Pharmaceutical activity, Pharmacokinetics, Permeability, Polymorphism, Thermal stability, Third-generation ionic liquids.