“…The predicted values of polar surface area (PSA) for the test ligands, conessine, kurchessine, isoconessimine, pubescine, holadienine, holanamine, conessimine, holadysenterine, kurchine, and loperamide, were 6.03, 5.76, 15.09, 50.49, 16.93, 39.05, 14.99, 74.72, 15.09, and 34.51 Å 2 , respectively ( Table 3 ). Lazerwith et al (2011) [ 55 ] reported that the PSA value of a compound has an inverse relationship with its lipid permeation capability. If the polar surface area (PSA) value of a drug is greater than 140 Å 2 , and HBA > 10, HBD > 5, and MW > 500, in that case it is quite likely that it (the drug) will have a limited cell membrane permeability [ 56 ].…”