Equations used to calculate remaining transport activity in presence of inhibitor in cell models
| Eq. No. | Name | Equationb | Reference |
|---|---|---|---|
| A1 a | ER | 1 – [(BA0 / AB0) – (BAi / ABi)] / [(BA0 / AB0) – (BAp / ABp)] can be written as: [(BAi / ABi) – (BAp / ABp)] / [(BA0 / AB0) – (BAp / ABp)] | Balimane et al. (2008) |
| A2 | ER (FDA) | (BAi / ABi – 1) / (BA0 / AB0 – 1) | US FDA/CDER (2006) |
| B1 | Unidirectional flux (B>A) | (BAi – BAp) / (BA0 – BAp) | Tang et al. (2002) |
| B2 | Unidirectional flux (A>B) | (ABi – ABp) / (AB0 – ABp) | Tang et al. (2002) |
| C1 | KP (A>B) | (ABi / AB0)[(ABi – ABp) / (AB0 – ABp)] | Kalvass and Pollack (2007) |
| C2 | KP (B>A) | (BA0 / BAi)[(BAi – BAp) / (BA0 – BAp)] | Adapted from Kalvass and Pollack (2007) |
| D | Net-secretory-flux | (ABi – BAi) / (AB0 – BA0) | Balimane et al. (2008) |
ER, efflux ratio.
↵a Equation A2 is the FDA-recommended equation (US FDA/CDER, 2006). For this particular initiative, due to the limited number of inhibitor concentrations in the cell line experiments, the participants were asked to fit data to eq. A1 so that a no inhibitor control and positive control inhibitor could be included as data points (see Materials and Methods section).
↵b ABi Receiver A>B with inhibitor; BAi Receiver B>A with inhibitor; AB0 Receiver A>B, without inhibitor; BA0 Receiver B>A, without inhibitor; ABp Receiver A>B with positive control; BAp Receiver B>A with positive control.