Comparison of nonlinear pharmacokinetic parameters estimated from the sinusoidal perfusion and venous equilibrium models.

It is shown that the intrinsic and steady-state clearances and the values of Vm and Km of the Michaelis-Menten equation estimated via the sinusoidal perfusion model are different from the corresponding values estimated via the venous equilibration model. The liver blood flow rates estimated by two theories (from plasma data) are identical. The comparison was made using the single dose oral and intravenous and steady-state oral plasma concentration-time data for verapamil in six subjects previously published.