Metabolism of bisphenol S in mice after oral administration

Rationale: As an important substitute of bisphenol A (BPA), bisphenol S (BPS) shows comparable estrogenic effects. BPS is now widely used in consumer products with widespread human exposure. In order to evaluate the health risk of BPS, it is essential to develop a rapid method for the determination of BPS and its metabolites as well as its biotransformation capacity in vivo. Methods: Two major BPS phase II metabolites, BPS glucuronide (BPS-G) and BPS sulfate (BPS-S), were synthesized and used as standards for the development of a ultra-performance liquid chromatography/electrospray ionization tandem mass spectrometry (UPLC/ESI-MS/MS) method. Phase II metabolism of BPS in imprinting control region (ICR) female mice after oral administration with different dosages (10, 100, 1000 mu g/kg body weight) was investigated. Results: Urinary elimination was the main excretion route for BPS, with the total recovery ranging from 52.8% to 78.1%. In urine, BPS-G was identified as the predominant metabolite, and the maximum concentrations of BPS-G and BPS-S were obtained at 6 h after the oral administration upon the adjustment by creatinine. BPS was the major compound existed in feces. Only trace amounts of BPS and its metabolites were detected in digestive and excretory related tissues (< 1%). Conclusions: The distribution and metabolic pathway of BPS in mice were assessed. More than 50% of BPS was excreted through phase II metabolism. Due to the biological inactivity of BPS-G and BPS-S, rapid metabolism of BPS to BPS-G and BPS-S may result in reduced toxicity of BPS in vivo.