title: Rapid determination of rivaroxaban in human urine and serum using colloidal palladium surface-assisted laser desorption/ionization mass spectrometry.
abstract: BACKGROUND
  Rivaroxaban is a new anticoagulant drug that has recently been introduced for clinical applications. To ensure optimum efficacy while minimizing the risk of toxicity and other adverse effects, a simple and sensitive analytical procedure for monitoring the concentration of rivaroxaban in biological fluids is required.
  
  
  METHODS
  Rivaroxaban was extracted from aqueous solutions by dispersive liquid-liquid microextraction (DLLME). Detection of rivaroxaban was achieved through surface-assisted laser desorption/ionization mass spectrometry (SALDI-MS) using colloidal palladium as the SALDI matrix.
  
  
  RESULTS
  The calibration curve for rivaroxaban in aqueous solutions was linear over the concentration range from 5 to 500 nM. The limit of detection (LOD) for rivaroxaban at a signal-to-noise ratio of 3 was 2 nM. With a sample-to-extract volume ratio of 200, the enrichment factors were calculated to be 141. This method was successfully applied for the determination of rivaroxaban in human urine and serum samples. The LODs for rivaroxaban in urine and serum were calculated to be 6 nM and 60 nM, respectively.
  
  
  CONCLUSIONS
  The analysis speed, together with the ease of operation and high sensitivity, allows SALDI-MS method to be particularly suitable for the high-throughput screening of rivaroxaban levels in human urine and serum samples.
authors.affiliation: Department of Chemistry, National Kaohsiung Normal University, No. 62, Shenjhong Road, Yanchao, Kaohsiung, Taiwan, 824.
authors.forename: Yu-Han
authors.initials: YH
authors.lastname: Cheng
authors.affiliation: Division of Gastroenterology, Department of Medicine, Kaohsiung Veterans General Hospital, 386 Ta-Chung 1st Road, Kaohsiung, Taiwan, 813.|Faculty of Medicine, School of Medicine, National Yang-Ming University, Taipei, Taiwan, 112.
authors.forename: Wen-Chi
authors.initials: WC
authors.lastname: Chen
authors.affiliation: Department of Chemistry, National Kaohsiung Normal University, No. 62, Shenjhong Road, Yanchao, Kaohsiung, Taiwan, 824.
authors.forename: Sarah Y
authors.initials: SY
authors.lastname: Chang
mesh_terms: D000925:Anticoagulants / Q000097:blood* / Q000652:urine*; D006801:Humans; D010165:Palladium / Q000737:chemistry; D000069552:Rivaroxaban / Q000097:blood* / Q000652:urine*; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*
chemical_list: D000925:Anticoagulants; D010165:Palladium; D000069552:Rivaroxaban