Effect of acetonitrile on tolbutamide hydroxylation in HL microsomes and in the CYP2C9-reconstituted system
| Kinetic Parameter | Acetonitrile Concentration | ||
|---|---|---|---|
| 0 | 2 | 4 | |
| HL Microsomes | |||
| % | |||
| V max (pmol · min−1 · mg protein−1) | 428 (25)4-150 | 826 (21) | 1095 (40) |
| K m (μM) | 113 (20) | 121 (8) | 126 (13) |
| CLmet(V max/K m) (μl · min−1 · mg protein−1) | 3.8 | 6.8 | 8.7 |
| % change in CL relative to 0% solvent | +79 | +129 | |
| RECO CYP2C9 System | |||
| V max(nmol · min−1 · nmol P-450−1) | 4.5 (1) | 6.9 (1) | 7.0 (1) |
| K m(μM) | 169 (83) | 108 (42) | 90 (42) |
| CLmet(V max/K m) (μl · min−1 · nmol P-450−1) | 26.6 | 63.9 | 78.0 |
| % change in CL relative to 0% solvent | +140 | +193 | |
↵4-150 Values in parentheses are nonlinear regression standard error.