Cytochrome P450 inhibition

Cytochromes P450 are a family of enzymes that play an important role in metabolism. There are about a hundred isoenzymes, of which 7 are considered the most important: CYP 1A2, CYP 2B6, CYP 2C8, CYP 2C9, CYP 2C19, CYP 2D6 and CYP 3A4. The latter alone is responsible for the metabolism of 50% of marketed drugs.

Assessing a compound's potential to inhibit CYP450 is important because of the risk of drug interaction. If more than one compound is co-administered, one may inhibit the metabolism of the other. This may affect plasma concentrations and potentially lead to adverse reactions or toxicity.

Protocol

MatrixMouse or human liver microsome (0,5mg/mL)
CofactorNADPH
Test concentrations0,01 ; 0,03 ; 0,1 ; 0.3 ; 1 ; 3 ; 10 et 30 μM.
Test temperature37°C
Incibation time60 min
Controls

Furafylline (1A2), clopidogrel (2B6),

nicardipine (2C8), sulfaphénazole (2C9),

oxybutinine (2C19), quinidine (2D6),

ketoconazole (3A4)

Analysis methodLCMS-MS
Data deliveryDose-reponse curve, IC50
Replicate2

 

Data

Note

Inhibition can also be assessed less thoroughly with only 2 concentrations (1 and 10 µM).
It is possible to assess the reversibility of the inhibition.