Table 1

Summary of assays to evaluate interaction with Pgp

Monolayer EffluxCalcein-AMATPase
Activity measuredTransportInhibitionATPase stimulation
Pgp sourceMDR1-MDCKIIMDR1-MDCKIIMDR1-Sf9 cell membranes
Analytical endpointLC/MS/MSFluorescenceAbsorbance
Throughput12 compounds/week200 compounds/week150 compounds/week
FTE requirements211
Criteria for (+) activityBA/AB ratio >2.01-a >10% of GF120918 responseATPase ratio >2.0
Nonconfident zoneBA/AB ratio 1.5 to 2.06–12%ATPase ratio 1.5 to 2.0
  • FTE, full time equivalent.

  • 1-a  A compound with a ratio of 1.5–2.0 will be classified as a Pgp substrate if the directional efflux is attenuated by the presence of 2 μM GF120918.