Table 2

Summary of correlation data between ezlopitant metabolism and cytochrome P450 isoform specific marker substrate activities2-a

CYP1A2CYP2C9CYP2C19CYP2D6CYP3A4
Correlation Coefficient (r2)
[S] = 0.3 μM
 Ezlopitant consumption0.3290.0200.2000.2430.389
 CJ-12,458 formation0.2950.0000.0400.3150.5982-b
 CJ-12,764 formation0.4530.0020.0650.3720.434
[S] = 10 μM
 Ezlopitant consumption0.3470.0050.0440.2800.6372-b
 CJ-12,458 formation0.3460.0020.0480.2490.6272-b
 CJ-12,764 formation0.4420.0020.0690.2170.485
[S] = 100 μM
 Ezlopitant consumption0.2560.0010.1370.0630.466
 CJ-12,458 formation0.3260.0040.0160.1740.7522-b
 CJ-12,764 formation0.3590.0030.0400.1140.6572-b
  • 2-a  Cytochrome P450 marker activities are as follows:

  • CYP1A2: phenacetin O-deethylase at [phenacetin] = 50 μM

  • CYP2C9: tolbutamide hydroxylase at [tolbutamide] = 200 μM

  • CYP2C19: S-mephenytoin 4′-hydroxylase at [S-mephenytoin] = 200 μM

  • CYP2D6: bufuralol 1′-hydroxylase at [bufuralol] = 10 μM

  • CYP3A4: testosterone 6β-hydroxylase at [testosterone] = 50 μM

  • 2-b  Correlation was statistically significant (P < 0.0005; Student's ttest).