Application of a substrate cocktail approach in the assessment of cytochrome P450 induction using cultured human hepatocytes.
Induction of the cytochrome P450 (CYP) family of enzymes by coadministered compounds can result in drug-drug interactions, as in the case of the coadministration of rifampicin with many CYP3A substrates, including midazolam. Identification of potential drug-drug interactions due to CYP induction during drug discovery is critical. We present a substrate cocktail method that was applied to assess the induction of CYP1A, CYP2B6, CYP2C9, and CYP3A using a 96-well high-throughput format. Viable cell counts were determined using a high-content screening system to normalize activities. Substrate cocktail incubations demonstrated a similar fold induction for known inducers as compared with discrete probe incubations. The system was further validated by determining the induction potency of rifampicin. The E(max) and EC(50) values in two separate lots of hepatocytes for CYP3A induction by rifampicin in a 96-well format were similar when discrete probe was compared with the probe cocktail. This system has been demonstrated to be suitable for high-throughput assessments of CYP induction.
Eisai, Inc., Andover, MA, USA. rbrtpelletier@gmail.com
Robert D
RD
Pelletier
W George
WG
Lai
Y Nancy
YN
Wong
D002478:Cells, Cultured; D003577:Cytochrome P-450 Enzyme System / Q000235:genetics / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D055808:Drug Discovery; D004789:Enzyme Activation / Q000187:drug effects; D005786:Gene Expression Regulation / Q000187:drug effects; D022781:Hepatocytes / Q000201:enzymology*; D006801:Humans; D012293:Rifampin / Q000494:pharmacology; D013379:Substrate Specificity
D003577:Cytochrome P-450 Enzyme System; D012293:Rifampin