Objective: Prediction of pharmacokinetic behaviour of new candidate drugs is an important step in drug design. Clearance is a key pharmacokinetic parameter, controlling drug exposure in the body. It depends on numerous factors and is frequently restricted by plasma protein binding. The study is focused on the development of quantitative structure-pharmacokinetic relationship (QSPkR) for the unbound clearance (CLu
Methods:The dataset consisted of 117 neutral drugs, divided into training set (n = 94) and external test set (n = 23). Chemical structures were encoded by 113 theoretical descriptors. Genetic algorithm and step-wise multiple linear regression were applied for model development. The model was evaluated by cross-validation in the training set and external test set.) of neutral drugs.Results: Significant, predictive and interpretable QSPkR model was developed with explained variance r 2 = 0.617, cross-validated correlation coefficient q 2 LOO-CV = 0.554, external test set predictive coefficient r 2 pred = 0.656, and root mean square error in prediction RMSEP = 1.89. The model was able to predict CLu
Conclusion:The model reveals the main molecular features governing CL for 56% of the drugs in the external test set within the 2-fold error of experimental values.u of neutral drugs. CLu Keywords: QSPkR, Clearance, Unbound clearance, In silico modelling, Prediction of ADME is favoured by lipophilicity, the presence of fused aromatic rings, ester groups, dihydropyridine moieties and nine-member ring systems, while polarity, molecular size and strong electron withdrawing atoms and groups as substituents in aromatic rings affect negatively CL