Results also indicated that compounds NAPROC-13 have stronger features of NPs as compared to the NPs in UNPD-A (average: 1.51; median: 1.51; standard deviation: 1.1). As expected, both NPs collections had higher values than compounds in the set of FDA-approved drugs (average: 0.02; median: -0.10; standard deviation: 1.1), which was used as a reference in the comparison. The distribution of NPL scores in Figure agreed with the values calculated previously for other NPs and approved drugs.