Kinetic constants of docetaxel oxidation to hydroxydocetaxel in rat, pig, minipig, and human liver microsomes The results are means of at least two experiments with microsomes pooled from six rats or one castrated minipig, a representative regular pig of three males or three females, and two male humans. Substrate concentrations used for docetaxel oxidation were 2 to 25 μM.
Microsomes | P450 Enzymes | Km | Vmax | Vmax/Km |
|---|---|---|---|---|
| μM | pmol/min/mg protein | |||
| Untreated rat | CYP3A1/2 | 5.6 | 52 | 9.1 |
| Minipig | CYP3A29 | 3.5 | 52 | 15 |
| 8.1 (males) | 23 (males) | 2.9 | ||
| Regular pig | CYP3A29 | 5.1 (females) | 21 (females) | 4.0 |
| Humansa | CYP3A3/4 | 3.9-6.9 | 11.8-23 | 0.3-16.2 |
↵ a Interval of kinetic constants from two male human microsmes