Polyesterurethanes have been shown to degrade by hydrolysis releasing 2,4-toluenediamine (2,4-TDA). Polyesterurethane has been used in medical implants, including breast implants, and it has been observed that 2,4-TDA has been released in vivo. The metabolites of 2,4-TDA are possible carcinogens, and their distribution in the rat body has been studied. These early rat studies where by ingestion, interperitoneal injection or IV introduction of 2,4-TDA. Using these published results a physiological based pharmacokinetic model has been developed for 2,4-TDA and its metabolites. An inhalation based introduction was also included in the model. The model can be used to predict the bioavailable dose of 2,4-TDA and its metabolites released from a polyesterurethane implant. This model forms the basis for predicting the fate of other components leached from other types of implants.