title: A sensitive LC/MS/MS method using silica column and aqueous-organic mobile phase for the analysis of loratadine and descarboethoxy-loratadine in human plasma.
abstract: A sensitive method using liquid chromatography with tandem mass spectrometric detection (LC/MS/MS) was developed and validated for the simultaneous analysis of antihistamine drug loratadine (LOR) and its active metabolite descarboethoxy-loratadine (DCL) in human plasma. Deuterated analytes, i.e. LOR-d(3) and DCL-d(3) were used as the internal standards (I.S.). Analytes were extracted from alkalized human plasma by liquid/liquid extraction using hexane. The extract was evaporated to dryness under nitrogen, reconstituted with 0.1% (v/v) of trifluoroacetic acid (TFA) in acetonitrile, and injected onto a 50 x 3.0 mm I.D. 5 microm, silica column with an aqueous-organic mobile phase consisted of acetonitrile, water, and TFA (90:10:0.1, v/v/v). The chromatographic run time was 3.0 min per injection and flow rate was 0.5 ml/min. The retention time was 1.2 and 2.0 min for LOR and DCL, respectively. The tandem mass spectrometric detection was by monitoring singly charged precursor-->product ion transitions: 383-->337 (m/z) for LOR, 311-->259 (m/z) for DCL, 388-->342 (m/z) for LOR-d(3), and 316-->262 (m/z) for DCL-d(3). The low limit of quantitation (LLOQ) was 10 pg/ml for LOR and 25 pg/ml for DCL. The inter-day precision of the quality control (QC) samples was 3.5-9.4% relative standard deviation (R.S.D.). The inter-day accuracy of the QC samples was 99.0-107.9% of the nominal values.
authors.affiliation: Covance Laboratories Inc., Department of Bioanalytical Chemistry, 3301 Kinsman Boulevard, Madison, WI 53704, USA. naidong.weng@covance.com
authors.forename: Weng
authors.initials: W
authors.lastname: Naidong
authors.forename: T
authors.initials: T
authors.lastname: Addison
authors.forename: T
authors.initials: T
authors.lastname: Schneider
authors.forename: X
authors.initials: X
authors.lastname: Jiang
authors.forename: T D J
authors.initials: TD
authors.lastname: Halls
mesh_terms: D002853:Chromatography, Liquid / Q000379:methods; D006801:Humans; D017336:Loratadine / Q000031:analogs & derivatives* / Q000097:blood* / Q000737:chemistry; D013058:Mass Spectrometry / Q000379:methods; D012822:Silicon Dioxide / Q000032:analysis; D013678:Technology, Pharmaceutical / Q000379:methods*
chemical_list: C086094:des(ethoxycarbonyl)loratadine; D012822:Silicon Dioxide; D017336:Loratadine