title: Simultaneous determination of levocetirizine and pseudoephedrine in dog plasma by liquid chromatography-mass spectrometry in the presence of dextrocetirizine.
abstract: OBJECTIVE
  This study describes the development of a rapid and sensitive LC-ESI-MS assay for simultaneous enantioselective determination of levocetirizine and pseudoephedrine in dog plasma in the presence of dextrocetirizine.
  
  
  METHODS
  Separations were achieved on an Ultron ES-OVM chiral column using the mobile phase consisting of 10 mM aqueous NH4OAc (pH 6.6) and acetonitrile (9:1 v/v).
  
  
  RESULTS
  The retention times of pseudoephedrine, dextrocetirizine, levocetirizine and diazepam (internal standard) were 5.2, 8.3, 9.6 and 11.6 min, respectively, and the total run time was less than 15 min. The assay was validated to demonstrate the linearity, accuracy and precision, recovery and stability. The calibration curves were linear over the concentration range from 1 - 200 ng/mL for levocetirizine and from 5 - 1000 ng/mL for pseudoephedrine.
  
  
  CONCLUSIONS
  The developed assay was successfully applied to a pharmacokinetic study after oral administration of the racemic cetirizine (0.5 mg/kg, or 0.25 mg/kg as levocetirizine) and pseudoephedrine (12 mg/kg) in the dog. This article is open to POST-PUBLICATION REVIEW. Registered readers (see "For Readers") may comment by clicking on ABSTRACT on the issue's contents page.
authors.affiliation: Department of Pharmaceutical Engineering, Sangji University, Wonju-si, 220-702, Korea.
authors.forename: Jae Kuk
authors.initials: JK
authors.lastname: Ryu
authors.forename: Sun Dong
authors.initials: SD
authors.lastname: Yoo
mesh_terms: D000284:Administration, Oral; D000818:Animals; D002138:Calibration; D017332:Cetirizine / Q000008:administration & dosage / Q000097:blood* / Q000493:pharmacokinetics; D002853:Chromatography, Liquid / Q000379:methods*; D003975:Diazepam / Q000097:blood; D004285:Dogs; D008297:Male; D013058:Mass Spectrometry / Q000379:methods; D054199:Pseudoephedrine / Q000008:administration & dosage / Q000097:blood* / Q000493:pharmacokinetics; D012015:Reference Standards; D012680:Sensitivity and Specificity; D013237:Stereoisomerism
chemical_list: C472067:levocetirizine; D054199:Pseudoephedrine; D003975:Diazepam; D017332:Cetirizine