Table 3

Kinetic parameters for the in vitro interaction of haloperidol and various CYP3A4 substrates in human recombinant CYP3A4 generated by multisite kinetic model approach (mean ± S.E.)

CYP3A4 substrateVmaxKsKiαγδ
pmol/min/pmol P450 μM
NIF3-a 13.3 ± 1.334.9 ± 3.90.25 ± 0.130.32 ± 0.040.08 ± 0.03
FELb 3.54 ± 0.3140.9 ± 8.73.4 ± 0.90.95 ± 0.290.58 ± 0.19
TST3-c 8.41 ± 0.19243 ± 1734 ± 130.05 ± 0.028.2 ± 4.1
  • The kinetic parameters were determined using two-site model:

  • 3-a eq. 3, β (changes in Kpfrom SES) = γ and b; the kinetic parameters were determined using the eq. 2 β = 2 (substrate-binding sites are equivalent) three-site model:

  • 3-c eq.5.