Ru(III) anticancer agents with aromatic and non-aromatic dithiocarbamates as ligands: Loading into nanocarriers and preliminary biological studies

Since the discovery of cisplatin in the 1960s, other metal complexes have been investigated as potential antitumor agents to overcome the side-effects associated with the administration of the Pt-based drug. In line with our previous research, in this work we report the synthesis and characterization of mono- and dinuclear Ru(III) complexes with the pyrrolidinedithiocarbamate (PDT) ligand and the more sterically-hindered carbazole-dithiocarbamato ligand (CDT), to compare their properties (both at the chemical and antiproliferative level), in an attempt to assess a structure-activity rationale. Moreover, to overcome the scarce solubility under physiological conditions of the Ru(III)-dithiocarbamato compounds, the biocompatible copolymer Pluronic® F127 has been used, to encapsulate the metal derivatives in water-soluble micellar carriers. Finally, preliminary biological evaluations on CDT and PDT compounds along with their nanoformulations, open intriguing perspectives in anticancer chemotherapy. In particular, comparing the structure of the Ru(III) derivatives, the ionic dinuclear PDT complex shows an important cytotoxic action in comparison to its neutral counterparts. Moreover, the micellar carrier improves the overall activity of the encapsulated Ru(III)-PDT chemotherapeutics. On the other hand, the nanoformulation of the CDT derivatives allows us to solubilize both the 1:3 and the 2:5 complexes and to state their inactivity.