Discussion

Drug metabolising enzymes, Cytochrome P450s (CYPs), may be inhibited by New Chemical Entities (NCEs) - a serious clinical safety concern when elevated plasma drug concentrations reach toxic levels. Human recombinant CYP membranes are useful in vitro to assess NCE potential to cause inhibition in vivo.

We developed a cassette based (pooled) assay to monitor inhibition of all 5 major CYPs simultaneously in one reaction, and compare IC50 values to those generated in our 5 individual unpooled assays to assess agreement of both assay formats.

Our results demonstrate excellent correlation (R2>0.9) between the IC50 values in both the pooled and unpooled assay formats. The pooled 5CYP assay followed by a 2-minute UPLC-LCMSMS detection method has significantly increased our efficiency to assess investigational new drugs in a high throughput setting.