“…PLS validation (cross-validation, non-cross-validation) of 3D-QSAR models is performed in sybyl2.0 software to obtain the best cross-validation coefficient ( q 2 ), the best principal component score ( n ), correlation coefficient ( r 2 ), F -value and standard deviation (SEE). 20 In internal validation, a responsible 3D-QSAR model must satisfy the following criteria. q 2 > 0.5, r 2 > 0.9, F value should be as large as possible, and SEE value should not.…”