ABSTRACT
Physiologically based pharmacokinetic (PBPK) modeling has become the tool of choice to develop estimates of target site dosimetries in both animals and humans. After dosing, animals can be maintained in metabolism cages designed to collect urine and feces separately. This chapter outlines some of the practical issues involved in the appropriate development of a PBPK model, so that costs may be kept to a minimum. In many cases, PBPK models have become necessarily complicated and, therefore, pose a risk communication problem. In developing a PBPK model, organs and tissues are represented as a finite number of individual compartments with their individual values for blood flow, tissue volume, and partition coefficients. Physiological and anatomical parameters also change during the life span of an organism, as well as during pregnancy, and attempts have been made to collect these kinds of data as well, and to incorporate the differences into specific PBPK models.
