Predicting Plasma Concentrations of Bisphenol A in Young Children Following Typical Feeding Schedules

Predicting Plasma Concentrations of Bisphenol A in
Young Children (< Two Years) Following
Typical Feeding Schedules

Environmental Health Perspectives

Full article: http://www.ehponline.org/members/2008/0800073/0800073.pdf

ABSTRACT

Background: Concerns have recently been raised regarding the safety of potential human
exposure to bisphenol A (BPA), an industrial chemical found in some polycarbonate
plastics and epoxy resins. Of particular interest is the exposure of BPA to young children
via food stored in BPA-containing packaging.

Objectives:

To assess the age-dependence of the toxicokinetics of BPA and its
glucuronidated metabolite, BPA-Glu, using a coupled BPA_BPA-Glu physiologicallybased
toxicokinetic (PBTK) model.

Methods:

Using information gathered from toxicokinetic studies in adults, a PBTK model
was built. The model was then scaled to young children under the age of 2 based on the
age-dependence of physiological parameters relevant for absorption, distribution,
metabolism and excretion.

Results:

The average steady state BPA plasma concentration in newborns is estimated to
be 11 times greater than that in adults when given the same weight-normalized dose. Due
to the rapid development of the glucuronidation process, this ratio is reduced to 2 by 3
months of age. Simulation of typical feeding exposures, as estimated by regulatory
authorities, showed a 5 times greater steady state BPA plasma concentration in 3 and 6
month olds when compared to adults. This was due to both a reduced capacity for BPA
metabolism as well as a greater weight-normalized BPA exposure. Due to an uncertainty
in defining the hepatic BPA intrinsic clearance in adults, these values represent
preliminary estimates.

Conclusions:

Simulation of the differential BPA dosimetry between adults and young
children point to the need for more sensitive analytical methods for BPA to define, with
greater certainty, the adult hepatic BPA intrinsic clearance, as well as, a need for external
exposure data in young children.