Over the past two decades, much effort has been devoted to identifying exemplary drugs, or probes, whose metabolism is catalyzed specifically by given human P450 enzymes. These metabolic probes have been characterized using expressed recombinant P450s as well as human liver microsomes in the presence of chemical inhibitors and/or specific P450 antibodies. As such, they serve as positive controls in P450 reaction phenotyping studies performed with new chemical entities. The drug-metabolizing assays shown below all meet regulatory agency requirements, and have been chosen due to their high degree of enzyme specificity and ease of use.

DICLOFENAC 4’-Hydroxylase - CYP2C9
PACLITAXEL 6-Hydroxylase CYP2C8