title: Quantification of human plasma-busulfan concentration by liquid chromatography-tandem mass spectrometry.
abstract: BACKGROUND
  Busulfan, an alkylating agent administered prior to hematopoietic stem cell transplantation, has a narrow therapeutic range and wide variability in metabolism. We developed a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for rapid and accurate quantification of plasma busulfan.
  
  
  METHODS
  Busulfan was separated and detected using an LC system containing a C18 column equipped with MS/MS. The sample was eluted with a mobile phase gradient for a total run time of 10 min. Plasma busulfan concentration was quantified against a 6-point standard curve in a multiple reaction monitoring mode at mass-to-charge (m/z) 264.1 > 151.1. Precision, recovery, matrix effect, linearity, detection capability, carryover, and stability were evaluated. The range of plasma busulfan concentration was obtained by analyzing samples from 9 children receiving busulfan.
  
  
  RESULTS
  The coefficients of variation of within-run and within-laboratory precision were all below 5%. Recoveries were all within the range of 100-105%. Linearity was verified from 0 to 5,000 ng/mL. Limit of detection and limit of quantification were 1.56 and 25 ng/mL, respectively. Carryover rate was within allowable limits. Plasma busulfan concentration was stable for 2 weeks at -20℃ and -80℃, but decreased by 25% when the plasma was stored for 24 hr at room temperature, and by <5% in 24 hr at 4℃. The plasma busulfan concentrations were between 347 ng/mL and 5,076 ng/mL.
  
  
  CONCLUSIONS
  Our method using LC-MS/MS enables highly accurate, reproducible, and rapid busulfan monitoring with minimal sample preparation. The method may also enable safe and proper dosage.
authors.affiliation: Department of Laboratory Medicine, Seoul National University Hospital, Seoul, Korea.
authors.forename: Soo Young
authors.initials: SY
authors.lastname: Moon
authors.affiliation: Department of Laboratory Medicine, Seoul National University Hospital, Seoul, Korea.
authors.forename: Min Kyoo
authors.initials: MK
authors.lastname: Lim
authors.affiliation: Department of Laboratory Medicine, Seoul National University Hospital, Seoul, Korea.
authors.forename: Susie
authors.initials: S
authors.lastname: Hong
authors.affiliation: Department of Laboratory Medicine, Seoul National University Hospital, Seoul, Korea.
authors.forename: Yongbum
authors.initials: Y
authors.lastname: Jeon
authors.affiliation: Department of Laboratory Medicine, Seoul National University Hospital, Seoul, Korea.
authors.forename: Minje
authors.initials: M
authors.lastname: Han
authors.affiliation: Department of Laboratory Medicine, Seoul National University Hospital, Seoul, Korea.
authors.forename: Sang Hoon
authors.initials: SH
authors.lastname: Song
authors.affiliation: Department of Pharmacology and Clinical Pharmacology, Seoul National University Hospital, Seoul, Korea.
authors.forename: Kyoung Soo
authors.initials: KS
authors.lastname: Lim
authors.affiliation: Department of Pharmacology and Clinical Pharmacology, Seoul National University Hospital, Seoul, Korea.
authors.forename: Kyung-Sang
authors.initials: KS
authors.lastname: Yu
authors.affiliation: Department of Pharmacology and Clinical Pharmacology, Seoul National University Hospital, Seoul, Korea.
authors.forename: In-Jin
authors.initials: IJ
authors.lastname: Jang
authors.affiliation: Department of Pediatrics, Seoul National University Hospital, Seoul, Korea.
authors.forename: Ji Won
authors.initials: JW
authors.lastname: Lee
authors.affiliation: Department of Pediatrics, Seoul National University Hospital, Seoul, Korea.
authors.forename: Hyoung Jin
authors.initials: HJ
authors.lastname: Kang
authors.affiliation: Department of Laboratory Medicine, Seoul National University Bundang Hospital, Seongnam, Korea.
authors.forename: Junghan
authors.initials: J
authors.lastname: Song
mesh_terms: D002066:Busulfan / Q000097:blood* / Q000592:standards; D002648:Child; D002675:Child, Preschool; D002851:Chromatography, High Pressure Liquid / Q000592:standards; D018380:Hematopoietic Stem Cell Transplantation; D006801:Humans; D007223:Infant; D011786:Quality Control; D012015:Reference Standards; D053719:Tandem Mass Spectrometry / Q000592:standards
chemical_list: D002066:Busulfan
keywords: Busulfan; Drug monitoring; Hematopoietic stem cell transplantation; Liquid chromatography; Tandem mass spectrometry