The docking protocol used performed well in distinguishing P-gp binders from non-binders within the Validation Set 1. Indeed, the average binding energy of the binders was -8.4 kcal/mol, which was lower than that obtained with non-binders (-7.3 kcal/mol) (Fig. ). While the statistical analysis showed that the difference is significant (p<0.001), it is smaller than the standard error of the AutoDock Vina scoring function (estimated to be around 2.8 kcal/mol 37 ). Hence, even if the discrimination power can be considered sufficiently reliable, care must be taken when using it for VS purposes.