A large set of default parameters (e.g. organ volumes, blood flows, volume of distribution) that can be called upon.  For example, all the values required for human studies are setup simply by a call to "standardhuman".  (The current version also implements a "standardrat").

A plot of the time course of GI absorption can be output, using, as input, the experimental venous blood levels after an oral intake.  A new technique is used to invert the model equations in order to obtain an accurate solution for the GI input.

The first pass liver metabolism and peripheral availability of a GI administered drug is directly determined (and plotted as output).  This determination uses a new definition of first pass metabolism that is applicable to the case of non-linear (saturable) liver metabolism.

Plasma and extracellular protein binding is treated rigorously and the option of non-linear (saturable) protein binding is included

Rigorous modeling of capillary permeability limitations.

The model of the lung used for the volatile solute incorporates ventilation-perfusion mismatch.

An arbitrary multiple dosage regimen can be simulated and plotted.

Any or all of the model parameters can be optimized to give the best fit to the experimental data using a rigorous global (simulated annealing) and/or local non-linear Powell minimization routine that has a simple interface.

The PBPK model human antecubital vein blood concentration can be output and plotted, and the antecubital vein concentrations can be used to refine the PBPK parameters.

An arbitrary number of simultaneously interacting solutes can be modeled.  Two types of interaction (competitive or non-competitive inhibition) are allowed.  Also, the case where some solutes are converted into other solutes can be modeled, with a separate Vm and Km for each substrate/product pair.