Comparative toxicokinetics of bisphenol S in rats and mice following gavage administration.

Bisphenol S (BPS) is a component of polyether sulfone used in a variety of industrial applications and consumer products. We investigated the plasma toxicokinetic (TK) behavior of free (unconjugated parent) and total (parent and conjugated) BPS in rats and mice following a single gavage administration (34, 110, or 340 mg/kg). In male rats, BPS was rapidly absorbed with free BPS maximum concentration (C-max) reached at <= 2.27 h. Elimination of free BPS in male rats was dose-dependent with estimated half-lives of 5.77-11.9 h. C-max and area under the concentration versus time curve (AUC) increased with dose although the increase in AUC was more than dose proportional. In male rats, total BPS C-max was reached <= 2.77 h with both C-max (> 10-fold) and AUC (> 15-fold) higher than free BPS demonstrating rapid and extensive conjugation of BPS. In male mice, the increase in C-max and AUC of free BPS was dose-proportional; C-max was higher and AUC was lower than in male rats. BPS was cleared more rapidly in male mice (half-life 2.86-4.21 h) compared to male rats (half-life 5.77-11.9 h). Similar to rats, total BPS C-max (>= 6-fold) and AUC (>= 12-fold) were higher than corresponding free BPS. Oral bioavailability of free BPS was low to moderate (rats, <= 21%; mice, <= 19%). There were some species differences in TK parameters of free and total BPS and limited sex difference in rats and mice. In addition, there were dose-related effects of plasma TK parameters in rats.