Validation of the 3D-QSAR Models

Eleven compounds that were not included in the training set were selected as a test data set to validate the QSAR models. All of the test compounds were well predicted. The mean and standard deviation of prediction errors were 0.28 and 0.005 for the CoMFA model, and only 0.33 and 0.011 for the CoMSIA model. The predictive which was analogous to the cross-validated correlation coefficient q, was 0.883 for the CoMFA and 0.908 for the CoMSIA, suggesting a high reliability of these models. 

The consistency between the CoMFA/CoMSIA field distributions and the 3D topology of the protein stmcture indicated the robustness of the 3D-QSAR models. Overall, the degree of predictability of the CoMSIA model appeared to be similar to that of the CoMFA model. The combined use of both the CoMFA and the CoMSIA model might be more suitable for the prediction of the activities of novel designed compounds [22]. 

---