Gayrard V, Lacroix MZ, Collet SH, Viguié C, Bousquet-Melou A, Toutain PL, Picard-Hagen N.
INRA, UMR1331, TOXALIM, Research Center in Food Toxicology; and Université de Toulouse, INPT, ENVT, EIP, UPS, Toulouse, France.
Abstract
BACKGROUND:
Bisphenol A (BPA) risk assessment is currently hindered by the rejection of reported higher than expected BPA plasma concentrations in humans after oral ingestion. These are deemed incompatible with the almost complete hepatic first-pass metabolism of BPA into its inactive glucurono-conjugated form, BPA glucuronide (BPAG).
OBJECTIVES:
Using dogs as a valid model, plasma concentrations of BPA were compared over a 24-h period after intravenous, orogastric and sublingual administrations, in order to establish the absolute bioavailability of BPA administered sublingually and to compare it with oral bioavailability.
METHODS:
Six dogs were sublingually administered with BPA at 0.05 mg/kg and 5mg/kg. The time course of plasma BPA concentrations was compared with that obtained in the same dogs after intravenous administration of the same BPA doses and after a 20mg/kg BPA dose administrated by orogastric gavage.
RESULTS:
The data indicated that the systemic bioavailability of BPA deposited sublingually was high (70-90%) and that BPA transmucosal absorption from the oral cavity led to much higher BPA internal exposure than obtained for BPA absorption from the gastro-intestinal tract. The concentration ratio of BPAG to BPA in plasma was approximately 100-fold lower following sublingual administration than after oral dosing enabling the two pathways of absorption to be easily distinguished.
CONCLUSIONS:
These findings demonstrate that BPA can be efficiently and very rapidly absorbed through the oral mucosa by the sublingual route. This efficient systemic entry route of BPA may lead to far higher BPA internal exposures than known for BPA absorption from the gastro-intestinal tract.
PMID: 23761051 [PubMed – as supplied by publisher] 1. Environ Health Perspect. 2013 Jun 12. [Epub ahead of print]