Figure 1:

Two schematic diagrams showing the structure of a generic PBPK model for rats (panel A) and humans (panel B). The parent compound is indicated by solid lines whereas metabolite is shown using broken lines. Inhalation, oral, and dermal exposure routes are shown with the model compartment that first receives the external concentration. The skin compartment for dermal exposure (panel B) is divided by a broken line to indicate separate treatment of exposed and unexposed skin areas in the model.