title: Comparison of levocetirizine pharmacokinetics after single doses of levocetirizine oral solution and cetirizine dry syrup in healthy Japanese male subjects.
abstract: OBJECTIVE
  Levocetirizine, the R-enantiomer of cetirizine, is classified as a second generation antihistamine used for the treatment of allergic disorders. This study aimed to compare exposure to levocetirizine when given as levocetirizine oral solution (OS) 5 mg to that when given as cetirizine dry syrup (DS) 10 mg, which contains equal proportions of levocetirizine and dextrocetirizine, in healthy Japanese male subjects.
  
  
  METHODS
  The study was conducted in an open-label, single dose, randomized and two-way cross-over design. Eligible subjects were allocated to one of two groups and received either levocetirizine OS 5 mg or cetirizine DS 10 mg under fasting conditions, and the alternate treatment after a 7-days washout period. Serial blood samples were taken after each administration, and plasma levocetirizine concentrations were determined using a validated LC-MS/MS method. Pharmacokinetic parameters were calculated by using non-compartmental analysis. Comparisons of levocetirizine pharmacokinetics were conducted with maximum concentration (C max) and the area under the plasma concentration-time curve from dosing until 48 h post-dose (AUC0-48) after each treatment.
  
  
  BACKGROUND
  ClinicalTrials.gov identifier is NCT01622283.
  
  
  RESULTS
  The mean C max and AUC0-48 of levocetirizine after a single dose of levocetirizine OS 5 mg and cetirizine DS 10 mg were 203.3 ± 42.49 ng/mL and 1814.9 ± 304.22 ng.hr/mL, and 196.5 ± 31.31 ng/mL and 1710.5 ± 263.31 ng hr/mL, respectively. The ratios and the 90% CIs of the geometric least squares means ratios of C max and AUC0-48 were 1.027 (0.968-1.091) and 1.059 (1.024-1.094), respectively.
  
  
  CONCLUSIONS
  The small sample size and single dose design of this study prevent definitive conclusions regarding the pharmacokinetics and safety of levocetirizine OS in a Japanese patient population being made. Study limitations include conducting the study in adult males, not in children.
  
  
  CONCLUSIONS
  Levocetirizine exposure in plasma was equivalent when given as levocetirizine OS 5 mg and as cetirizine DS 10 mg. Both preparations were safe and well-tolerated in healthy Japanese male subjects.
authors.affiliation: Medicines Development (Clinical Pharmacology), Development & Medical Affairs Division, GlaxoSmithKline K.K., TokyoJapan.
authors.forename: Hiroko
authors.initials: H
authors.lastname: Ino
authors.affiliation: Medicines Development (Clinical Pharmacology), Development & Medical Affairs Division, GlaxoSmithKline K.K., TokyoJapan.
authors.forename: Katsutoshi
authors.initials: K
authors.lastname: Hara
authors.affiliation: Biomedical Data Sciences Department, Development & Medical Affairs Division, GlaxoSmithKline K.K., TokyoJapan.
authors.forename: Gosuke
authors.initials: G
authors.lastname: Honma
authors.affiliation: Medicines Development (Clinical Pharmacology), Development & Medical Affairs Division, GlaxoSmithKline K.K., TokyoJapan.
authors.forename: Yohei
authors.initials: Y
authors.lastname: Doi
authors.affiliation: CPC Clinical Trial Hospital, Medipolis Medical Research Institute, KagoshimaJapan.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Fukase
keywords: Cetirizine; Japanese; Levocetirizine; Pharmacokinetics