Kinetics of orally administered di(2-ethylhexyl) phthalate and its metabolite, mono(2-ethylhexyl) phthalate, in male pigs

Di(2-ethylhexyl) phthalate (DEHP) is used as a plastic softener in the polymer industry and is widespread in medical devices. DEHP has been incriminated as an endocrine-disrupting chemical, and the effects of DEHP in various species have included disturbances in the reproductive system. The effects of the chemical have varied, depending upon exposure routes and species. This study was performed in order to characterise the kinetics of DEHP and its metabolite mono(2-ethylhexyl) phthalate (MEHP) in the young male pig, an omnivore model-species for research in reproductive toxicology. Eight pigs were given 1000 mg DEHP/kg bodyweight by oral gavage. The concentrations of DEHP and MEHP were then measured in the plasma and tissues of the pigs at different time points after administration. There was no consistent rise above contamination levels of concentrations of DEHP in the plasma of the pigs. However, the metabolite MEHP reached the systemic blood circulation. The half-life of MEHP in the systemic blood circulation was calculated to be 6.3 h. Absorption from the intestine was biphasic in six of the eight pigs and the mono-exponential elimination-phase started 16 h after the after the administration of DEHP. To conclude, MEHP consistently reaches the systemic circulation in the pig when DEHP is administered orally. The kinetic pattern of the parent substance on the other hand is more difficult to characterise.