Metal chelates as anti-cancer agents. II cytotoxic action of palladium and platinum complexes of 6-mercaptopurine and thioguanine.

The metal complexes Pd(MP)2.2H2O, Pt(MP)2H2O (MPH=6-mercaptopurine), Pt(AMP2.3H2O and Pd3(AMP)4Cl2(AMPH).4H2O (AMPH=thioguanine) have been isolated. They were screened for anti-tumour activity in the L-1210 lymphoid leukaemia test system in mice. All 4 show marked anti-tumour activity, the complex Pt(AMP)2.3H2O giving a T/C of 185 at the optimum dosage. However, the anti-tumour activity of the metal complexes is somewhat less than that shown by the parent purines under the same conditions.