Drug pharmacokinetics and toxicokinetics -- GIT anatomy and physiology and drug oral bioavailability : impact of species differences -- Drug routes of excretion -- Physicochemical and biopharmaceutical properties that affect drug absorption of compounds absorbed by passive diffusion -- Physicochemical and biopharmaceutical factors affecting hepatic/intestinal first pass effect -- Impact of intestinal efflux transporters on oral absorption -- Impact of influx transporters on drug -- Extended Clearance Classification System (ECCS) and its utility in predicting clearance rate determining step in drug discovery -- In vitro and in situ approaches to measure intestinal permeability and efflux transporters -- In silico approaches to predict intestinal permeability -- In vivo preclinical approaches to deconvolute the contribution of first pass effect from oral absorption -- In vitro approaches to assess haptic metabolism and first pass effect -- The utility of ECCS as a roadmap to improve oral bioavailability of new molecular entities : industrial perspective.