A quantitative correlation of the LC₅₀ values of esters in pimephales promelas using physicochemical and topological parameters

In recent years much emphasis has been given to the development of easily calculated molecular descriptors that can adequately predict the pharmacological and toxic action of bioactive molecules. In this article a quantitative structure‐activity relationship (QSAR) study of industrially important esters was carried out using hydrophobicity (log P, octanol‐water), molecular connectivity indices (^lX, ^lX^v), Wiener number (W) and information‐theoretic topological indices defined on the total molecular graph. Information‐theoretic topological indices studied include information content (IC), structural information content (SIC) and complementary information content (CIC), as well as information indices derived from the distance matrix of the hydrogen‐suppressed chemical graph (I^W_D, I ^W_D). The topological index ^lX^v, an electronic parameter, was found to be the single best descriptor for predicting the LC₅₀ values of esters in Pimephales promelas. However, a multiparametric relationship including a lipophilic (log P), an electronic (^l_X^v) and a steric (CIC) parameter resulted in the most significant correlation, suggesting multiconditionality in the mode of toxic action of these esters.