TIME DEPENDENT CYP INHIBITION

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Inhibitory effect of CYP may lead to clinically relevant drug-drug interaction. Time dependent CYP Inhibition evaluates the reversible and irreversible (time dependent) interaction. 

This IC50 shift by 30 minute pre-incubation in the presence of NADPH enables discrimination between compounds which cause reversible and irreversible inhibitions. Once the IC50 shift is detected, the apparent inactivation constant (KI) and the maximal inactivation rate constant (kinact) are determined to estimate the potential DDI risk.

Time Dependent CYP Inhibition Assay Protocol:

Test article concentration: 30,10, 3.3, 1.1, 0.37, 0.12, 0.041 and 0  µM (other upon  request) 

Preincubation time: 30 min -/+ NADPH 

Incubation time: 5 to 45 minutes as per the isoform 

Incubation temperature: 37 C 

Number of Replicates: n = 2  

Assay condition: Phosphate buffer 

Assay matrix: CYP1A2, CYP2B6, CYP2C8, CYP2C9, CYP2C19, CYP2D6 and CYP3A4   (other isoforms are available) 

Controls: Known isoform specific inhibitors 

Analysis Method: LC/MS/MS 

Data Delivery: IC50, IC50 shif