title: Determination of lumefantrine in small-volume human plasma by LC-MS/MS: using a deuterated lumefantrine to overcome matrix effect and ionization saturation.
abstract: BACKGROUND
  To support pediatric study, a method to determine lumefantrine (LF) with small sample volume is needed. Matrix effect (ME) is a daunting issue in LF quantification in human plasma with LC-MS/MS.
  
  
  RESULTS
  Here we report an LC-MS/MS method with a deuterated LF as the internal standard (IS). Plasma sample (25 µl) was acidified with 5% formic acid prior to extraction with ethyl acetate. The recovery was over 80%. The absolute ME was within the range of 100 ± 8% for both LF and the IS, but cumulative ME was observed via large variation of IS signal. The cumulative ME and ionization saturation were overcome with the co-eluting LF-D(9) as the IS. The linear range of calibration curve was 50-20,000 ng/ml.
  
  
  CONCLUSIONS
  ME and ionization saturation was overcome with a deuterated IS. The method utilized a small sample volume, suitable for pediatric study with capillary tube blood collection method.
authors.affiliation: Drug Research Unit, Department of Clinical Pharmacy, School of Pharmacy, University of California, San Francisco, CA 94110, USA. huangl@sfghsom.ucsf.edu
authors.forename: Liusheng
authors.initials: L
authors.lastname: Huang
authors.forename: Xiaohua
authors.initials: X
authors.lastname: Li
authors.forename: Florence
authors.initials: F
authors.lastname: Marzan
authors.forename: Patricia S
authors.initials: PS
authors.lastname: Lizak
authors.forename: Francesca T
authors.initials: FT
authors.lastname: Aweeka
mesh_terms: D000962:Antimalarials / Q000097:blood*; D002138:Calibration; D002853:Chromatography, Liquid / Q000379:methods*; D004983:Ethanolamines / Q000097:blood*; D005449:Fluorenes / Q000097:blood*; D006801:Humans; D000078102:Lumefantrine; D012015:Reference Standards; D015203:Reproducibility of Results; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*; D053719:Tandem Mass Spectrometry / Q000379:methods*
chemical_list: D000962:Antimalarials; D004983:Ethanolamines; D005449:Fluorenes; D000078102:Lumefantrine