Finite dose pharmacokinetics of skin penetration

A model for estimating in vivo skin permeability coefficients for finite doses is presented. The ratio of the maximum value of the excretion rate to the steady-state flux is a function of the thickness of the applied vehicle and the vehicle-skin partition coefficient. The decay rate of the excretion is a function of skin-vehicle parameters for large doses and, under certain conditions, can even reduce to the total excretory rate constant as the dose is decreased.