Accurate estimates for the oral bioavailability of hydrophobic contaminants bound to solid matrices are challenging to obtain because of sorption to organic matter. The purpose of this research was to measure the bioavailability of [14C]chrysene sorbed to soil using an in vitro model of gastrointestinal digestion and absorption to a surrogate intestinal membrane, ethylene vinyl acetate (EVA) thin film. The [14C]chrysene moved rapidly from soil into the aqueous compartment and reached steady state within 2 h. Equilibrium was reached in the EVA film within 32 h. Aging the spiked soil for 6 or 12 months had no effect on chrysene mobilization. This was supported by the finding that the data best fit a one-compartment model. Despite significant decreases in [14C]chrysene mobilization when water or nonneutralized gastrointestinal fluids were used in place of the complete medium, the equilibrium concentration of [14C]chrysene in EVA film remained the same in all conditions. Thus, the driving force for uptake was the fugacity gradient between the aqueous phase and the EVA film. Cultured human enterocytes (human colorectal carcinoma cell line [Caco-2 cells]) had a higher lipid-normalized fugacity capacity than EVA film, but the elimination rate constants were the same, suggesting that the rate was controlled by the resistance of the unstirred aqueous layer at the membrane–water interface.
If you can't find a tool you're looking for, please click the link at the top of the page to "Go to old article view". Alternatively, view our Knowledge Base articles for additional help. Your feedback is important to us, so please let us know if you have comments or ideas for improvement.