BACKGROUND: apixaban (BMS-562247) (Eliquis(®)) is a novel, orally active, 
selective, direct, reversible inhibitor of the coagulation factor Xa (FXa). A 
sensitive and reliable method was developed and validated for the measurement of 
apixaban (BMS-562247) and its major circulating metabolite (BMS-730823) in human 
citrated plasma for use in clinical testing.
METHODOLOGY/RESULTS: A 0.100 ml portion of citrated plasma sample was extracted 
and analyzed by LC-MS/MS. Run times were approximately 3 min. The lower limit of 
quantification (LLOQ) was 1.00 ng/ml for BMS-562247 and 5.00 ng/ml for 
BMS-730823. Intra- and inter-assay precision values for replicate QC control 
samples were within ≤5.36% for both analytes (≤7.52% at the LLOQ). The accuracy 
for both analytes was within ±9.00%.
CONCLUSION: The method was demonstrated to be sensitive, selective and robust, 
and was successfully used to support clinical studies.