Table 2.
Astemizole metabolism in recombinant P450s.
| P450 form | DES-AST formation | NOR-AST formation | 6OH-AST formation |
|---|---|---|---|
| CYP1A1 | ND | ND | ND |
| CYP1A2 | ND | ND | ND |
| CYP2A6 | ND | ND | ND |
| CYP2B6 | ND | ND | ND |
| CYP2C8 | ND | ND | ND |
| CYP2C9 | ND | ND | ND |
| CYP2C18 | ND | ND | ND |
| CYP2C19 | ND | ND | ND |
| CYP2D6 | 8.1 | ND | 26.5 |
| CYP2E1 | ND | ND | ND |
| CYP3A4 | ND | 4.6 | 3.6 |
| CYP4A11 | ND | ND | ND |
Metabolite formation rate using microsomes from yeast cell expressing each P450 isoform were shown except for CYP4A11. 10 µm[14C]-astemizole was incubated for 60 min with 100 pmol ml−1 of microsomes from yeast cell expressing each P450 isoform. Not detectable (ND): <2 nmol nmol−1 P450 60 min−1. For CYP4A11, 10 µm[14C]-astemizole was incubated for 60 min with 39 pmol ml−1 of microsomes from lymphoblastoid cell expressing CYP4A11 (ND: <5.1 nmol nmol−1 P450 60 min−1). Values are expressed as nmol nmol−1 P450 60 min−1.