Tumor Inhibiting Properties of Stereoisomeric [1,2‐Bis (3‐hydroxyphenyl)ethylenediamine]dichloroplatinum(II)‐Complexes, Part II: Biological Properties

The activity of stereoisomeric [1,2‐bis (3‐hydroxyphenyl)ethylenediamine]dichloroplatinum(II)‐complexes (1‐PtCl 2 , R, S; 2 ‐PtCl 2 , R, R/S, S; 3 ‐PtCl 2 , R, R; 4 ‐PtCl 2 , S, S) on several tumor models (MDA‐MB 231 breast cancer cell line; P 388 leukemia, mouse; L 1210 leukemia, mouse; L 5222 leukemia, rat; Ehrlich ascites tumor, mouse ‐ wildtype; cisplatin‐, etoposide‐, cyclophosphamide‐, and daunomycin‐resistent, resp.) is described. For comparison the analogous [1,2‐bis(4‐hydroxyphenyl)ethylendiamine]dichloroplatinum(II)‐complexes ( 5 ‐PtCl 2 , R, S; 6 ‐PtCl 2 , R, R/S, S; 7 ‐PtCl 2 , 8 ‐PtCl 2 , S, S) and cisplatin are used. 1 ‐PtCl 2 to 4 ‐PtCl 2 (OH in 3,3′‐positions) show their maximum antitumor effect at lower doses than 5 ‐PtCl 2 to 8 ‐PtCl 2 (OH in 4,4′‐positions). 2 ‐PtCl 2 and 6 ‐PtCl 2 (R, R/S, S) are more active than 1 ‐PtCl 2 and 5 ‐PtCl 2 (R, S). 4 ‐PtCl 2 and 8 ‐PtCl 2 (S, S) are superior to 3 ‐PtCl 2 and 7 ‐PtCl 2 S, S). On the L 5222 leukemia 2 ‐PtCl 2 (R, R/S, S), 4 ‐PtCl 2 (S, S) and 8 ‐PtCl 2 (S, S) markedly surpass cisplatin. Strong effects are produced by 2 ‐PtCl 2 to 4 ‐PtCl 2 on the Ehrlich ascites tumor (wildtype, cisplatin‐, etoposide‐, cyclophosphamide‐, and daunomycin‐resistent, resp.). The combination of 4 ‐PtCl 2 with cisplatin results in a weakly synergistic effect.