IC50 values (μM) for inhibition of 2C9 activities in human liver microsomes
| Tolbutamide Methyl Hydroxylase | ||
|---|---|---|
| Without NADPH | With NADPH | |
| Amlodipine | 14 | 14 |
| Diltiazem | >150 | >150 |
| Felodipine | 18 | 26 |
| Nicardipine | 7 | 9 |
| Nifedipine | 32 | 31 |
| Verapamil | >100 | >100 |
| Sulfaphenazole | 0.5 | 0.5 |
Incubations were performed in duplicate or triplicate for each concentration of inhibitors by preincubation of inhibitors with or without NADPH for 30 min before adding the substrate.