October 3, 2018

Assay System: 

  • Human liver microsomes, pooled from 50 donors.
  • Inhibition potential of test compound measured upon incubation with human liver microsomes at different compound concentrations. Reversible inhibition is determined by monitoring activity of individual CYP enzymes using isoform-specific probe substrates with LC-MS/MS detection.

Assay Conditions:

Test Compound ConcentrationEight concentrations ranging from 0.05 µM to 100 µM
Percent Organic Solvent in Incubation2% acetonitrile
CYP Isoforms Available for TestingCYP1A2, CYP2B6, CYP2C8, CYP2C9, CYP2C19, CYP2D6, and CYP3A4
Incubation Time10-20 minutes (depending on CYP isoform)
pH7.4
Temperature37 °C
AnalysisLC-MS/MS
Number of Repeats2

Deliverable: IC50 of test compound and positive control compound.

Test Compound Requirement: 1-2 mg dry powder or 100-200 µL of 10 mM acetonitrile stock solution.

CYP IsoformProbe SubstrateMonitored MetabolitePositive Control Inhibitor
1A2PhenacetinAcetaminophenFurafylline
2B6BupropionOH BupropionTiclopidine HCl
2C8AmodiaquineDesethylamodiaquineMontelukast
2C9Tolbutamide4’-OH TolbutamideSulfaphenazole
2C19S-Mephenytoin4’-OH Mephenytoin(+)-N-3-Benzylnirvanol
2D6DextromethorphanDextrorphan-D-TartrateQuinidine
3A4Testosterone6β-OH TestosteroneKetoconazole
3A4Midazolam1’-OH MidazolamKetoconazole

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