Thursday, September 13, 2018
12:00 p.m. - 1:00 p.m. EST
K. Barry Delclos, Ph.D.
Division of Biochemical Toxicology
FDA’s National Center for Toxicological Research
About the Presentation
Bisphenol A (BPA) is a high-production-volume industrial chemical used in producing polycarbonate plastics and epoxy resins used in consumer products, such as storage containers for foods and beverages, medical devices, and thermal paper. The predominant human exposure is from food containers. Low levels of monomer can migrate from these products and there has been much controversy as to the potential toxicity of this BPA exposure.
FDA, under an Interagency Agreement between NCTR and the National Institute of Environmental Health Sciences, has conducted a series of studies in the past decade to address data gaps the FDA Science Board identified. Pharmacokinetic studies across several species have indicated that BPA undergoes rapid and extensive metabolic inactivation in the gut and liver, with the degree of inactivation in young animals varying across species.
FDA scientists developed physiologically based pharmacokinetic models that allow prediction of internal exposures to BPA in target organs of humans across all life stages. BPA toxicity was assessed in rats across a broad dose range, from about 10-fold to greater than 25,000-fold mean 90th percentile human dietary exposures. For the two-year toxicology study, animals and tissues were shared with 14 academic laboratories that assessed endpoints not typically included in guideline regulatory studies. The academic results will not be discussed in this presentation, but will be integrated later with the NCTR data. Results of the NCTR toxicity studies indicated that BPA produced adverse effects at high doses, but not at the low end of the dose range tested, consistent with its activity as a weak estrogen. These results will inform ongoing BPA safety assessments, a topic of considerable public interest.
About the Presenter
Dr. Barry Delclos is a Research Pharmacologist at FDA’s National Center for Toxicological Research, where he has been since 1985. His early research efforts focused on chemical carcinogenesis and later shifted to toxicities associated with endocrine active agents and modulation of toxicity by dietary factors. Dr. Delclos has served as Principal Investigator on a series of studies conducted under and Interagency Agreement between FDA and the National Institute of Environmental Health Sciences to evaluate aspects of the hypothesis that exposure to low levels of hormonally active agents, particularly during development, adversely affects human health, including reproductive function and carcinogenesis. These studies have been designed to address data gaps and provide data of usefulness in safety assessments conducted by FDA and other regulatory agencies.