title: Therapeutic monitoring of serum digoxin for patients with heart failure using a rapid LC-MS/MS method.
abstract: OBJECTIVE
  Here we develop a liquid chromatography tandem mass spectrometry (LC-MS/MS) method for the determination of digoxin in serum.
  
  
  METHODS
  The serum samples were extracted with methyl tert-butyl ether using an isotope-labeled digoxin-d3 as internal standard. The analyte was separated on a reverse phase Capcell C18 column and detected in positive electrospray ionization multiple reaction monitoring mass spectrometry.
  
  
  RESULTS
  The chromatographic analysis was carried out within 3 min, but the complete analysis took longer because of the liquid-liquid extraction. The lower limit of quantification was 0.1 ng/mL for digoxin. The intra- and inter-batch precisions were less than 12%, and the bias ranged from -9.1% to 10.7%. The external quality assessment (EQA) results obtained with the LC-MS/MS method were comparable to target values. Subsequently, this method has been applied to the therapeutic monitoring of digoxin in a clinical setting.
  
  
  CONCLUSIONS
  In this study, we have developed a rapid and reliable LC-MS/MS method for the therapeutic monitoring of digoxin in human serum.
authors.affiliation: Central Laboratory, Shanghai Xuhui Central Hospital, 966 Huaihai Middle Road, Shanghai 200031, China. lishuijun@gmail.com
authors.forename: Shuijun
authors.initials: S
authors.lastname: Li
authors.forename: Gangyi
authors.initials: G
authors.lastname: Liu
authors.forename: Jingying
authors.initials: J
authors.lastname: Jia
authors.forename: Yi
authors.initials: Y
authors.lastname: Miao
authors.forename: Shuiming
authors.initials: S
authors.lastname: Gu
authors.forename: Peizhi
authors.initials: P
authors.lastname: Miao
authors.forename: Xueying
authors.initials: X
authors.lastname: Shi
authors.forename: Yiping
authors.initials: Y
authors.lastname: Wang
authors.forename: Chen
authors.initials: C
authors.lastname: Yu
mesh_terms: D002853:Chromatography, Liquid / Q000379:methods*; D004077:Digoxin / Q000097:blood* / Q000627:therapeutic use; D006333:Heart Failure / Q000097:blood* / Q000188:drug therapy; D006801:Humans; D015394:Molecular Structure; D011786:Quality Control; D015203:Reproducibility of Results; D053719:Tandem Mass Spectrometry / Q000379:methods*
chemical_list: D004077:Digoxin