  The subject of analysis is a non-linear three-compartment model, widely used
in pharmacological absorption studies. It has been transformed into a general
form, thus leading automatically to an appropriate approximation. This made the
absorption profile accessible and expressions for absorption times, apparent
permeabilities and equilibrium values were given. These findings allowed a
profound analysis of results from non-linear curve fits and delivered the
dependencies on the systems' parameters over a wide range of values. The
results were applied to an absorption experiment with multidrug
transporter-affected antibiotic CNV97100 on Caco-2 cell monolayers.
