Prediction of water-to-polydimethylsiloxane partition coefficient for some organic compounds using QSPR approaches

A Quantitative Structure - Property Relationship (QSPR) model based on Genetic Algorithm (GA), Multiple Linear Regression (MLR) and Artificial Neural Network (ANN) techniques was developed for the prediction of water-to-polydimethylsiloxane partition coefficients (log K (PDMS-water)) of 139 organic compounds. A suitable set of molecular descriptors was calculated and important descriptors were selected by genetic algorithm and stepwise multiple regression. These descriptors were: Minimum Atomic Orbital Electronic Population (P (fufu)), Kier Shape Index (order 3) (K-3), Polarity Parameter / Square Distance (PP), and Complementary Information Content (order 2) ((CIC)-C-2). In order to find a better way to depict the nonlinear nature of the relationships, these descriptors were used as inputs for a generated ANN. The root mean square errors for the neural network calculated log K (PDMS-water) of training, test, and validation sets were 0.116, 0.179, and 0.183, respectively, which are smaller than those obtained by MLR model (0.422, 0.425, and 0.480, respectively). The results obtained showed the ability of developed artificial neural network to predict water-to-polydimethylsiloxane partition coefficients of various organic compounds. Also, the results revealed the superiority of the artificial neural network over the multiple linear regression model.