Antitumor activity of ionic liquids on human tumor cell lines

Ionic liquids (ILs) have emerged as new class of compounds with unique properties and potential to tailor their physiochemical properties. However, very limited studies have been reported on their toxicity and safety causing concern for their use for biomedical applications, specifically as therapeutic agents and drugs. Our studies towards finding therapeutic applications of ILs for the first time demonstrated the anti-cancer activity and cytotoxicity of three different classes of ionic liquids (imidazolium, phosphonium and ammonium) on National Cancer Institute's 60 human tumor cell lines. In this chapter an overview of these results is presented through representative examples. The preleminary structure-activity relationship (SAR) showed that the chain length of alkyl substitution on the cations plays crucial role towards anti-tumor activity and cytotoxicity of ionic liquids. In general, phosphonium-based ILs were found to be more active and less cytotoxic as compared to their ammonium amd imidazolium conterparts. In-vitro cell line data and hollow fiber study has demonstrated the potential of ILs to be developed as therapeutic agent.