Pharmacokinetics of loratadine and its active metabolite descarboethoxyloratadine in healthy Chinese subjects.
OBJECTIVE
To investigate the pharmacokinetics of loratadine (LOR) and its active metabolite descarboethoxyloratadine (DCL) in healthy Chinese subjects.


METHODS
Twenty healthy Chinese male subjects received a single oral dose of LOR 20 mg. A sensitive liquid chromatography-tandem mass spectrometry method (LC/MS/MS) was used for the determination of LOR and DCL in plasma.


RESULTS
Mean maximum concentration (C(max)) was found (17+/-14) microg/L for LOR at 1.2 h and (16+/-9) microg/L for DCL at 1.5 h. Mean area under the plasma concentration-time curve from zero to infinity (AUC(0-infinity)) was (47+/-49) microg x h x L(-1) for LOR and (181+/-122) microg x h x L(-1) for DCL, respectively. The apparent elimination half-life (T1/2) of LOR was (6+/-4) h, and that of DCL was (13.4+/-2.6) h. The ratios of AUC(DCL)/AUCLOR ranged from 0.36 to 54.5.


CONCLUSIONS
LOR was rapidly absorbed and transformed to DCL. AUC of the parent drug was extremely variable, while AUC of the active metabolite DCL was moderately variable after an oral dose of LOR to Chinese subjects.
Zhang
Yi-Fan
YF
Laboratory of Drug Metabolism and Pharmacokinetics, Shenyang Pharmaceutical University, Shenyang 110016, China.
Chen
Xiao-Yan
XY
Zhong
Da-Fang
DF
Dong
Yu-Mei
YM
D000284:Administration, Oral; D000328:Adult; D000982:Antipruritics / Q000378:metabolism / Q000493:pharmacokinetics*; D019540:Area Under Curve; D044466:Asian People; D006801:Humans; D017336:Loratadine / Q000378:metabolism / Q000493:pharmacokinetics* / Q000031:analogs & derivatives; D008297:Male; D010880:Piperidines / Q000378:metabolism*; D011725:Pyridines / Q000378:metabolism*
D000982:Antipruritics; D010880:Piperidines; D011725:Pyridines; D017336:Loratadine; C121345:desloratadine