In vivo rifampin Emax estimated using eq. 1 or 5, in vitro data from CYP3A4 mRNA or activity EC50 values, and our in vivo dataset of rifampin DDIs (n = 18) with intravenously administered CYP3A4 substrates
| In Vitro System | In Vivo Emax (eq. 1a) | In Vivo Emax (eq. 5b) | ||
|---|---|---|---|---|
| mRNA | Activity | mRNA | Activity | |
| Fa2N-4 | 8.8 | 9.5 | 45.6 | 49.2 |
| HepaRG | 2.9 | 10.0 | 15.1 | 51.9 |
| Cryopreserved hepatocytes | 3.4 | 2.0 | 17.4 | 10.5 |
| Primary hepatocytes | 8.3 | 2.8 | 42.9 | 14.6 |
a Based on static induction model with no EH incorporated.
b Hepatic extraction ratios of the substrates listed in Table 1 were incorporated in the prediction model, as defined in eq. 5.