Table 2.
Data sets used for model development/verification and available in Supporting information
| Study type | Description of data collected | Summary of data sets available in Supporting information | Reference |
|---|---|---|---|
| Single IV dose of TBA (37.5, 75, 150 and 300 mg kg−1) to male and female F344 rats | TBA blood concentrations up to 24 h post‐dose administration | Data were captured from figures 1 and 2 of publication using Plot Digitizer version 2.6.3, http://plotdigitizer.sourceforge.net and converted from μm to mg l−1 using the molecular weight of TBA (74.12 g mol−1). | Poet et al., 1997 |
| Single oral gavage dose (1 or 500 mg kg−1 14C–TBA) to male SD rats | Equations reported for TBA equivalents in blood over time measured in blood/plasma at 0.5, 3, 6 and 12 h following administration | Data from the cited study (tables 11, 15 and figures 6 and 8) were extracted from this report and recalculated for use in the model based on the assumption that the distribution between blood and plasma =1. | ARCO Chemical Company (1983)* |
| Inhalation exposure to nominal TBA concentrations (250, 450 and 1750 ppm) for 6 h day−1 for 1 or 8 days to male and female F344 rats | TBA blood and kidney concentrations following a single 6 h exposure (1 day) at 2, 4 and 6 h post‐exposure | These data were available from conduct of the actual experiments and used in the MTBE‐TBA model. Ratio of the kidney/blood levels was calculated and data provided. | Leavens & Borghoff, 2009; Borghoff et al., 2001 |
| Inhalation exposure to ETBE nominal concentrations (4.0 or 40 ppm) for 4 h to male and female F344 rats | ETBE and TBA blood concentration at the end of the 4 h exposure, amount of TBA up to 34 h post‐exposure and cumulative metabolite excretion as percentage of dose. | ETBE and TBA blood concentrations from table 5 from the study cited. TBA blood concentrations from exposure were corrected for reported background concentrations. Urinary amounts of TBA (mean ± SD) versus post‐exposure time were digitized from figure 4 from the study cited and corrected for background amount per sample based on the mean total background amount reported in table 5 of the study cited and the number of sample points (5). Corrected cumulative amount or TBA per time was calculated from the amount in urine at each post‐exposure time point. | Amberg et al., 2000 |
| Single oral gavage dose (5 and 400 mg kg−1 bw [14C]‐ETBE) SD rats | Plasma and urine samples collected up to 168 h post‐administration. Metabolites in plasma and urine were analyzed to examine chemical structures. Metabolite P5 was identified as TBA. | Concentration of TBA in blood was calculated from total radioactivity in blood following administration of 14C–ETBE, and the amount of TBA identified in the sample by HPLC at 8 h post‐administration of 5 or 400 mg kg−1 bw. At the 24 h urine collection, a combination of the total radioactivity in the samples and the % of the radioactivity determined to be TBA was used to calculate the total mg of TBA. | Japan Petroleum Energy Center (JPEC) (2008b)a |
| Repeated (14 days) oral gavage dose (5 mg kg−1 bw day−1 [14C]‐ETBE) SD rats | Plasma and urine samples collected at 7 and 14 days post‐administration. Metabolites in plasma and urine were analyzed to examine chemical structures. Metabolite P5 was identified as TBA. | Concentration of TBA in blood was calculated from total radioactivity in blood following administration of 14C–ETBE and the amount of TBA identified in the sample by HPLC at 8 h post‐administration of 5 or 400 mg kg−1. At the 24 h urine collection, a combination of the total radioactivity in the samples and the % of the radioactivity determined to be TBA was used to calculate the total mg of TBA. | Japan Petroleum Energy Center (JPEC) (2008c)a |
| Single (nose only) and repeated (14 days) (whole body, 13 days/nose only, 1 day) inhalation exposure (500, 1750 and 5000 ppm) – 14C‐ETBE‐F344 rats | Exhaled breath samples collected up to 16 h post‐exposure to ETBE for a single day. ETBE and TBA were quantitated in samples collected. % of the total dose eliminated in urine and exhaled was also provided. | Cumulative amount of ETBE and TBA exhaled or eliminated in urine was calculated from the level quantitated at each time point collected. | Borghoff and Asgharian (1996)a |
ETBE, ethyl tertiary‐butyl ether; MTBE, methyl tertiary‐butyl ether; SD rats, Sprague–Dawley (rats); TBA, tertiary‐butyl alcohol.
a
Experimental design, methods and data sets used for model development and verification are presented in Supporting information.