Fig. 3. HLM:HH CLint ratio compared with ER determined in (A) Caco-2 cells and (B) MDCK-MDR1 cells. Where, the solid red horizontal line represents no difference in scaled HLM and HH CLint, the dashed red horizontal lines represent a 2-fold difference in scaled HLM and HH CLint, and the solid red vertical line represents the efflux transporter substrate categorization; ≥2 = efflux substrate, <2 = not an efflux substrate. Symbols represent the main metabolizing enzyme: ●, UGT; ○, CYP3A; ■, CYP2D6; ▲, CYP2C; ♦, CYP1A; and *, Other. In Caco-2, the number of compounds from each metabolizing enzyme group was: UGT n = 3, CYP3A n = 22, CYP2D6 n = 7, CYP2C n = 4, CYP1A n = 0, and Other n = 5. In MDCK-MDR1, UGT n = 1, CYP3A n = 16, CYP2D6 n = 5, CYP2C n = 2, CYP1A n = 2, and Other n = 2.