TABLE 1

Experimental conditions for the measurement of P450 activity in pooled cryopreserved human hepatocytes

EnzymeMarker ActivitySubstrate ConcentrationCHHIncubation TimeMass transition MonitoredIonization ModeInternal Standard
μMmillion cells/mlminm/z
CYP1A2Phenacetin O-deethylation200.510152/110ESI+d4-Acetaminophen
CYP2B6Bupropion hydroxylation100.510256/167ESI+d6-Hydroxybupropion
CYP2C8Amodiaquine N-dealkylation30.510328/283ESI+d3-N-Desethylamodiaquine
CYP2C9Tolbutamide hydroxylation200.510287/171ESI+d9-Hydroxytolbutamide
CYP2C19S-Mephenytoin 4′-hydroxylation50.510235/150ESI+d3-4′-Hydroxymephenytoin
CYP2D6Dextromethorphan O-demethylation10.510258/157ESI+d3-Dextrorphan
CYP2E1Chlorzoxazone 6-hydroxylation450.510184/120ESI–d2-6-hydroxychlorzoxazone
CYP3A4Midazolam 1′-hydroxylation20.510342/324ESI+13C3-1′-Hydroxymidazolam
  • ESI, electrospray ionization.