2.3.  Pharmacokinetic (PK) parameters prediction
Drug discovery process requires early prediction of ADMET properties of candidate drug molecules. The fate of a therapeutic drug in an organism can be predicted conveniently by employing a user-friendly interface of SwissADME (http://www.swissadme.ch.). The server predicts important properties like lipophilicity (LIPO), flexibility (FLEX), TPSA, size, unsaturation (INSATU), insolubility (INSOLU) and bioavailability. Another online program admetSAR v1.0 (http://lmmd.ecust.edu.cn/admetsar2/) calculates and predicts physicochemical properties like lipophilicity (LIPO) of a query compound (XLOGP3) by using a known logP value of a reference compound as a starting point (Teague et al., 1999). The percentage of sp-hybridized carbons in the overall carbon count (Fraction Csp3) in the saturation percentage should be at least 0.25 (Tian et al., 2015). For solubility, log S (calculated with the ESOL model) should not exceed 6 (Delaney, 2004). admetSAR is also used to predict physiological and biochemical properties of a prospective drug candidate like human intestinal absorption (HIA), blood–brain barrier (BBB) permeability, Caco-2 penetration, P-glycoprotein inhibitor, Ames test-based mutagenesis, subcellular localization, biodegradation and acute oral toxicity.