3.4.  Pharmacokinetic properties
The pharmacokinetic property is the prime factor for the selection of a drug candidate that describes the drug disposition in the body. The significant parameters that quantify the pharmacokinetics of a drug are its ADME (absorption, distribution, metabolism, excretion) properties (Jang et al., 2001). All the molecules subjected to ADME tests are qualified for drug approval with their high value of gastrointestinal (GI) absorption (Daina & Zoete, 2016), which in turn implies for their use as an oral drug. Table 1 represents the pharmacokinetic properties of the proposed drug candidates. The passive GI absorption and blood–brain barrier (BBB) permeation is a fundamental criterion for the distribution of the drug molecules. From Table 1, it is observed that all the ligand molecules are BBB permeant that implies their underlying distribution index. The high negative skin permeable coefficient (Kp) values indicate a less skin permeability that is useful for their transdermal delivery. The interaction of the drug molecules with cytochromes P450 (CYP) is an essential property as they play a crucial role in drug elimination through biotransformation metabolism. The noninhibition of CYP isoforms such as CYP1A2, CYP2C19, CYP2C9, CYP2D6 and CYP3A4 disclose that these molecules are not the substrate for these enzymes that resembles for the lower degradation rate of these molecules, which will make it effectively available for blocking the SARS-CoV-2 RBD Spro and SARS-CoV-2 Mpro. The synthetic accessibility values suggest the facile synthesis of these molecules. All these parameters infer these close to drug-like molecules, which may be used as successful drug candidates.