Figure 6.

Correlation between the overall metabolism rate of cisapride, or the formation of norcisapride, and the metabolism of CYP substrates. The metabolism rates of two specific probes for CYP3A4 were correlated with the metabolism of ¹⁴C-cisapride, and norcisapride formation, in the presence of 16 different batches of human liver microsomes. The correlation with erythromycin N-demethylation or cyclosporin A-oxidase was determined by linear regression analysis. The correlation between the CYP3A4 substrate metabolism and the metabolism of cisapride (B,D) and formation of norcisapride (A,C) was significant (P⩽0.05).