Table 4.
Comparison of model predictions in blood with observed data using Sum of Square Error (SSE)
| Study | SSEa | Ratio of SSE for current model compared with Salazar et al. (2015)b | |
|---|---|---|---|
| ETBE‐TBA model presented | Salazar et al. (2015) | ||
| TBA IV (Poet et al., 1997) | 1.24E + 06 | 3.89E + 06 | 0.3 |
| TBA inhalation (Leavens & Borghoff, 2009); includes both single and repeat | 7.14E + 04 | 7.74E + 04 | 0.9 |
| TBA gavage (ARCO, 1983; unpublished report); blood | 3.71E + 05 | 1.36E + 05 | 2.7 |
| TBA gavage (ARCO, 1983; unpublished report); urinary excretion percentage | 5.27E + 03 | 8.26E + 03 | 0.6 |
| TBA blood concentrations following ETBE gavage (JPEC, 2008b; single) | 6.42E + 01 | 2.17E + 03 | 0.03 |
| TBA blood concentrations following ETBE gavage (JPEC, 2008c; repeated) | 3.17E+00c | 2.3E+00c | 1.4 |
| TBA cumulative in urine following ETBE gavage (JPEC, 2008b; single) | 2.22E + 01 | 1.13E‐01d | 2.0E2 |
| Percentage dose exhaled versus excreted following ETBE gavage (JPEC, 2008b; single) | 9.94E + 01 | 2.85E + 04 | 0.004 |
| ETBE blood concentrations following ETBE inhalation study (Amberg et al., 2000) | 1.25E + 00 | 3.45E‐01 | 3.6 |
| TBA blood concentrations following ETBE inhalation study (Amberg et al., 2000) | 7.11E‐01 | 3.40E + 00 | 0.2 |
| Percentage dose excreted following ETBE inhalation study (Amberg et al., 2000) | 2.41E + 01 | 1.45E + 02 | 0.2 |
| Cumulative TBA in urine following ETBE inhalation study (Amberg et al., 2000) | 7.65E‐05 | 8.22E‐03 | 0.01 |
ETBE, ethyl tertiary‐butyl ether; TBA, tertiary‐butyl alcohol.
a
Estimated from square of difference between predicted value and observed data for study.
b
Ratios less than one indicate a better prediction of data with current model and are shaded for emphasis.
c
Fits for both models are improved if no induction is assumed for TBA metabolism.
d
Note that the TBA urine was closer to the measured because of lower urinary elimination, which results in TBA blood concentrations with a larger discrepancy compared to measured values.