Receptor binding, cellular uptake and bioavailability of drug molecules is strongly influenced by molecular lipophilicity and molar refractivity. Both of them signify hydrophobic and dispersive (van der Waals) interactions (Ghose & Crippen, 1987) of a drug molecule and are employed in 3D-QSAR studies to evaluate the drug-like character of molecules under study (Viswanadhan et al., 1990, 1991). The following are the qualifying parameters for a putative drug candidate as per Ghose filter:clogP range between -0.4 and 5.6, with an average value of 2.52;
MW range between 160 and 480, with an average value of 357;
Molar refractivity range between 40 and 130, with an average value of 97;
Total number of atoms between 20 and 70, with an average value of 48.