Two-compartment itraconazole model with 4-transit absorption compartments connected to a one-compartment hydroxyitraconazole model with mixed linear (first-order) and nonlinear (Michaelis-Menten) hydroxyitraconazole elimination. KTR, transit absorption rate constant; Q, intercompartmental clearance; V2 and V3, central and peripheral volume of distribution of itraconazole, respectively; CLP, clearance of the parent drug; CLnon-lin, nonlinear hydroxyitraconazole clearance; V8, volume of distribution for the metabolite.