Structural identifiability and indistinguishability of certain two-compartment models incorporating nonlinear efflux from the peripheral compartment

A two-compartment model is considered where both compartments are observed and where the transfer efflux from the peripheral compartment may take three different nonlinear forms. The structural identifiability of the set of unknown parameters of each possible model is examined using the similarity transformation approach. Using the recent extension of this approach the indistinguishability of pairs of the postulated systems is also considered.