Combining the platinum(ii) drug candidate kiteplatin with 1,10-phenanthroline analogues

Platinum complexes of the type [Pt(P_L)(A_L)]²⁺ where P_L is a derivative of 1,10-phenanthroline and A_L is cis-1,4-diaminocyclohexane (1,4-dach), have been synthesised and characterised by ultraviolet spectroscopy, elemental microanalysis, nuclear magnetic resonance and X-ray crystallography. The calf-thymus DNA binding affinity of these complexes was determined by isothermal titration calorimetry, revealing higher DNA affinity than their 1S,2S-diaminocyclohexane analogues. In vitro cytotoxicity was assessed in eleven human cell lines, revealing unexpectedly low activity for the 1,4-dach complexes.