TABLE 5

kinact (min−1) estimates for the different CYP3A preparations obtained from inactivation experiments

Calculation of kinact was based on the loss of midazolam 1′-hydroxylation activity. See Table 4 for additional details.


Inhibitor

HL Microsomes

Supersomes
CYP3A4 (n = 3)
CYP3A5 (n = 2)
CYP3A4 + b5
CYP3A5 + b5
Erythromycin 0.046 ± 0.010 0.015 0.042 ± 0.007 0.011 ± 0.0003
Diltiazem 0.015 ± 0.007 ND 0.030 ± 0.0002 0.007 ± 0.001
Nicardipine
0.060 ± 0.01
ND
0.082 ± 0.02
0.023 ± 0.005
  • ND, not determined.