Oxidovanadium complexes with organic
ligands are well known to have cytotoxic or differentiating capabilities against a range of
cancer cell types. Their limited use in clinical testing though has resulted largely from uncertainties about the long-term toxicities of such complexes, due in part to the speciation to
vanadate ions in the circulation. We hypothesised that more highly stable complexes, delivered using
liposomes, may provide improved opportunities for oxidovanadium applications against
cancer. In this study we sourced specifically hydrophobic forms of oxidovanadium complexes with the explicit aim of demonstrating liposomal encapsulation, bioavailability in cultured
neuroblastoma cells, and effective cytotoxic or differentiating activity. Our data show that four
ethanol-solubilised complexes with
amine bisphenol, aminoalcohol bisphenol or salan
ligands are equally or more effective than a previously used complex bis(maltolato)oxovanadium(V) in
neuroblastoma cell lines. Moreover, we show that one of these complexes can be stably incorporated into cationic
liposomes where it retains very good bioavailability, apparently low speciation and enhanced efficacy compared to
ethanol delivery. This study provides the first proof-of-concept that stable, hydrophobic oxidovanadium complexes retain excellent cellular activity when delivered effectively to
cancer cells with nanotechnology. This offers the improved prospect of applying oxidovanadium-based drugs in vivo with increased stability and reduced off-target toxicity.