Table 1

Kinetic parameters for the formation of MI from metoclopramide (0–150 μM) in HLMs

MicrosomesKinetic parameters of M1
Vmax1-aKm1-bVmax/Km1-c
HLMs
 HL161237832.9
 HL3124721.7
 HL HK 23188513.7
 HL09-14-991-d 101411950.8
  Mean ± S.D.183  ± 5768  ± 162.8  ± 1.0
Recombinant human P450
 CYP2D66.4  ± 4.553.3  ± 4.10.12  ± 0.09

Data are the results from two independent duplicate incubations (n = 4 determinations).

  • 1-a  Vmax, picomoles per minute per milligram of protein in HLMs (or picomole per minute per picomole of P450 in recombinant CYP2D6).

  • 1-b  Km, micromolar concentration.

  • 1-c  Vmax/Km, microliter per minute per milligram of protein (or microliter per minute per picomole of P450 in recombinant CYP2D6). The mean is calculated without kinetic values from HL09-14-99.

  • 1-d  The kinetics for the formation of M1 from metoclopramide was difficult to estimate precisely because of nonsaturable kinetics.