Description
Omeprazole sulfone is the major metabolite of the gastric proton pump inhibitor, omeprazole . It is produced by cytochrome P450 (CYP)3A4 sulfoxidation of esomeprazole and is found in plasma. Omeprazole sulfone has been shown to act as a reversible direct-acting and metabolism-dependent inhibitor of CYP2C19 in pooled human liver microsomes (IC
50 = 18 μM).
in vivo
three hours after intake of 20 mg omeprazole only, the geometric mean plasma concentration of omeprazole sulfone were 106 nmol/l in 22 samples from subjects known to be extensive cyp2c19 metabolizers (em) and 672 nmol/l in the five subjects known to be poor cyp2c19 metabolizers (pm). the mean log10(omeprazole/omeprazole sulfone) ratio was 0.18 [4].
References
[1] nebert d w, russell d w. clinical importance of the cytochromes p450[j]. the lancet, 2002, 360(9340): 1155-1162.
[2] bel a, andersson t b, antonsson m, et al. stereoselective metabolism of omeprazole by human cytochrome p450 enzymes[j]. drug metabolism and disposition, 2000, 28(8): 966-972.
[3] nebert d w, russell d w. clinical importance of the cytochromes p450[j]. the lancet, 2002, 360(9340): 1155-1162.
[4] bttiger y. use of omeprazole sulfone in a single plasma sample as a probe for cyp3a4[j]. european journal of clinical pharmacology, 2006, 62(8): 621-625.
