Cytotoxicity of Asymmetric Platinum Complexes against L-1210 Cells. Effect of Bulky Substituents

Abstract

The asymmetric platinum complexes cis-Pt(LL')Cl₂ (L=NH₃, L'=CH₃NH₂, (CH₃)₂NH, C₂H₅NH₂ and (C₂H₅)NH and LL'=N, N-dimethylethylenediamine), -one of the NH₃ groups of cis-Pt(NH₃)₂Cl₂ was substituted by alkylamine-, were synthesized and their cytotoxic effects have been measured using L-1210 cells. The IC₅₀ values of the asymmetric platinum complexes, -being obtained after 24 h exposure of L-1210 cells to the platinum complexes-, are almost comparable to the corresponding value of cis-Pt(NH₃)₂Cl₂. lIn 2 h exposure, however, the IC₅₀ values of the platinum complexes were dramatically chaged, i.e., a marked difference was observed between those of L'=RNH₂ and L'=R₂NH. On the other hand, the amounts of platinum taken into the L-1210 cells is little affected by the alkylamino substitution. The results suggest that the bifunctional platinum binding to the target molecule may be responsible for the cytotoxicity.