Structure-antitumour activity relationships for new platinum complexes.

Fourteen platinum (Pt) coordination complexes with different ligands, which include both Pt(II) and Pt(IV) complexes, were prepared, characterized and tested for their in vitro cytotoxic effects on KB cells and for their antitumour activity against some tumour systems (L1210 and P388 leukaemia, ADJ/PC6A plasma cell tumour and Yoshida sarcoma). The majority of the ligands were derivatives of aniline or pyridine, but complexes with tranylcypromine, guanethidine and octodrine were also synthetized. Depending on cytotoxicity the Pt-compounds could be divided into 3 groups. The compounds with a high cytotoxicity (ED50 = 0.1-1 microgram/ml) were also active against L1210 and P-388 leukaemia; a correlation between cytotoxicity and antitumour activity was not always observed. In these complexes the oxidation state of the Pt appears to be critical for their activity.