Determination of anaprazole in human plasma by LC-MS/MS in pharmacokinetic study

: Anaprazole is a proton pump inhibitor clinically used for curing peptic ulcer. A rapid, sensitive and convenient LC-MS/MS method was first established for the determination of anaprazole in human plasma. d(3), (13)C-anaprazole was used as internal standard (IS). After extraction from human plasma by protein precipitation with acetonitrile, all components were separated on an Extend C(18) column (100 mm × 4.6 mm, 3.5 μm). The assay was linear over the concentration range of 5.00-3 000 ng·m L(-1) (r(2) > 0.995). The method was successfully applied to a pharmacokinetic study of 40 mg anaprazole enteric-coated tablets in 14 Chinese healthy volunteers under fasting or high fat diet conditions. C(max) was (1 020 ± 435) ng·m L(-1) and AUC(0-t) was (2 370 ±754) h·ng·m L(-1) under fasting condition. And C(max) was (538 ± 395) ng·m L(-1) and AUC(0-t) was (1 610 ± 650) h·ng·m L(-1) under high fat diet condition. The plasma results suggest that the exposure of anaprazole is reduced by the high fat diet.