Letter to the Editor: Mean Hepatic Recovery Ratio in Capacity-Limited First-Pass Effect by Three-Point Sampling Method

Recently,a three-point sampling method (portal and hepatic veins, and systemic artery) was developed to evaluate a capacity-limited first-pass effect through the liver (1). In this paper, the hepatic recovery ratio, F_H, increased to unity with an increase in the concentration of 5-fluorouracil in the blood entering the liver. Under steady-state conditions, the hepatic clearance, CL_H, of pravastatin decreased with an increase in the concentration in the arterial blood (2). The capacity in hepatic metabolism can be saturated or the hepatic local disposition can be nonlinear. Therefore, an index is needed to characterize nonlinear local hepatic disposition in the whole body (in loci).