Comparison Of Levocetirizine Pharmacokinetics After Single Doses Of Levocetirizine Oral Solution And Cetirizine Dry Syrup In Healthy Japanese Male Subjects

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 (AUC(0-48)) after each treatment.Clinical Trial registration number:ClinicalTrials.gov identifier is NCT01622283Results:The mean C-max and AUC(0-48) 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 Cmax and AUC(0-48) were 1.027 (0.968-1.091) and 1.059 (1.024-1.094), respectively.Limitation: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.