Multiparametric Quantitative Analysis of Rh₂(H₂cit)₄ Cytotoxicity in Human Breast Cell Lines

Rhodium(II) complexes have been investigated as potential anticancer agents. IC₅₀ provides a useful summary of cytotoxic potency, whereas complementary metrics describe additional aspects of the concentration-response profile. This study applied a multiparametric framework to previously published viability data for MCF-7 tumour cells and MCF-10A nontumourigenic breast epithelial cells exposed to free Rh₂(H₂cit)₄ for 24, 48 and 72 h. Four-parameter logistic models were fitted separately for each cell line and exposure time. The fitted curves were used to calculate IC₂₀, IC₅₀, absolute and relative benchmark concentrations, normalised area under the curve and selectivity indices. IC₅₀ decreased from 496.2 to 322.6 μmol/L in MCF-7 cells and from 251.7 to 149.7 μmol/L in MCF-10A cells between 24 and 72 h. IC₅₀-based selectivity indices remained below unity, indicating greater sensitivity of MCF-10A cells. Additional threshold and integral metrics supported this interpretation and characterised differences in curve shape, low-effect concentrations and overall viability across the analysed concentration range. The results provide a detailed quantitative description of the published concentration-time-response profiles and support multiparametric analysis as a complement to IC₅₀-based assessment in follow-up evaluation of selected in vitro datasets.