Influence of saliva, gastric and intestinal phases on the prediction of As relative bioavailability using the Unified Bioaccessibility Research Group of Europe Method (UBM).

In this study, As-contaminated soils (n=12) were assessed for As bioaccessibility using the Unified Bioaccessibility Research Group of Europe in vitro method (UBM) incorporating gastric, saliva-gastric or saliva-gastric-intestinal phases. Arsenic bioaccessibility was compared to previous published As relative bioavailability data for these soils to determine the correlation between in vitro and in vivo data. Comparison of in vitro and in vivo data indicated that the correlation between As bioaccessibility (UBM) and As relative bioavailability (swine assay) was similar irrespective of the in vitro phase used for its determination. The UBM incorporating all phases (saliva-gastric-intestinal) provided the best in vivo-in vitro correlation (slope=1.08; R(2)=0.59), however there was no significant difference in the goodness of fit (R(2) ranged from 0.48 to 0.59) or the slope of the lines (0.93-1.08) for either variation of the UBM (P=0.9946). This indicates that there was no improvement in the As relative bioavailability predictive capabilities when the UBM was extended from a single gastric phase to saliva-gastric or saliva-gastric-intestinal phases.