The First tetrafluorinated azobenzene-imidazolium ionic conjugates as potential thermotropic liquid crystalline drugs: Self-assembly properties and cytotoxic effects

Recent Advances in Biocompatible Ionic Liquids in Drug Formulation and Delivery

The development of effective drug formulations and delivery systems for newly developed or marketed drug molecules remains a significant challenge. These drugs can exhibit polymorphic conversion, poor bioavailability, and systemic toxicity, and can be difficult to formulate with traditional organic solvents due to acute toxicity. Ionic liquids (ILs) are recognized as solvents that can improve the pharmacokinetic and pharmacodynamic properties of drugs. ILs can address the operational/functional challenges associated with traditional organic solvents. However, many ILs are non-biodegradable and inherently toxic, which is the most significant challenge in developing IL-based drug formulations and delivery systems. Biocompatible ILs comprising biocompatible cations and anions mainly derived from bio-renewable sources are considered a green alternative to both conventional ILs and organic/inorganic solvents. This review covers the technologies and strategies developed to design biocompatible ILs, focusing on the design of biocompatible IL-based drug formulations and delivery systems, and discusses the advantages of these ILs in pharmaceutical and biomedical applications. Furthermore, this review will provide guidance on transitioning to biocompatible ILs rather than commonly used toxic ILs and organic solvents in fields ranging from chemical synthesis to pharmaceutics.

Safe and selective anticancer agents from tetrafluorinated azobenzene-imidazolium ionic liquids: Synthesis, characterization, and cytotoxic effects

A new series of tetrafluorinated azobenzene-imidazolium salts is reported. The azobenzene and imidazolium moieties were functionalized with long alkyl chains and connected via a methylene spacer of varying lengths (n = 3-12). They were characterized using FTIR and NMR spectroscopy, and elemental microanalysis. The cytotoxic potential of these ionic dimers against neuroblastoma (SHSY-5Y), estrogen-positive breast cancer cells (MCF-7), triple-negative breast cancer cells (MDA-MB-231), cervical cancer cells (HeLa), and human skin fibroblasts (Hs27) was evaluated using the MTT assay. The cytotoxicity of these ionic liquids (ILs) was dependent on the spacer length. A cut-off effect was observed, wherein the cytotoxicity of the ILs was enhanced by increasing the nonpolar, hydrophobic spacer length up to a threshold and the potency was leveled off upon chain elongation. All ILs exhibited selective and remarkable inhibition potentials against HeLa cells in a dose-dependent manner, which was 2-22 times stronger than that of etoposide, a clinical anticancer drug. These ILs were less toxic toward skin fibroblasts as implied by much higher IC₅₀ values. The long-spacer ILs (n = 7-10) were very selective toward HeLa cells. They had a broad safety window with selectivity indices ranging between 5.6 and 11.0. The selectivity of these compounds toward HeLa cells may serve as a new strategy for the design and development of safe and effective chemotherapeutics.