Quantitative structure–toxicity relationship (QSTR) studies on the organophosphate insecticides

•A QSTR model of some insecticides by using experimental LD50 values was produced.•First time, the toxicity of organothiophosphate type insecticides were estimated theoretically.•The most effective parameter in the QSTR model was logP values of insecticides.•Mass and molar refractivity of insecticides have moderate effect on the QSTR model.•The less effective parameter in the QSTR model was polarizability values of insecticides. Organophosphate insecticides are the most commonly used pesticides in the world. In this study, quantitative structure–toxicity relationship (QSTR) models were derived for estimating the acute oral toxicity of organophosphate insecticides to male rats. The 20 chemicals of the training set and the seven compounds of the external testing set were described by means of using descriptors. Descriptors for lipophilicity, polarity and molecular geometry, as well as quantum chemical descriptors for energy were calculated. Model development to predict toxicity of organophosphate insecticides in different matrices was carried out using multiple linear regression. The model was validated internally and externally. In the present study, QSTR model was used for the first time to understand the inherent relationships between the organophosphate insecticide molecules and their toxicity behavior. Such studies provide mechanistic insight about structure–toxicity relationship and help in the design of less toxic insecticides.