title: Validated ion pair liquid chromatography/fluorescence detection method for assessing the variability of the loratadine metabolism occurring in bioequivalence studies.
abstract: Inter- and intra-individual variability of the loratadine (LOR) metabolism in Caucasian subjects was assessed during a bioequivalence study for two pharmaceutical formulations (solid oral dosage forms) containing 10 mg of the active substance. The analytical data were obtained by applying a reliable, low-cost and sensitive ion pair liquid chromatography/fluorescence (IPLC/FLD) method for determination of both loratadine and descarboethoxyloratadine (DCL) in human plasma samples. The sample preparation procedure is based on liquid-liquid extraction of the target analytes from alkalinized plasma using diethyl-ether. The separation of the analytes and 8-chloroazatadine as internal standard (IS) was achieved through an isocratic ion pair (IP) elution on a Purospher((R)) STAR RP-18 column. The mobile phase containing sodium dodecyl sulfate (SDS) as ion pairing agent was pumped at a flow rate of 1 mL/min. Fluorescence detection (FLD) was achieved at 280 nm (excitation) and 440 nm (emission) wavelengths. The increased sensitivity of the method is also based on a large sample injected volume (250 microL). Linear response was found over the 0.5-20 ng/mL concentration interval for both target compounds. Low limits of quantification (LLOQ) around 0.3 ng/mL were found for LOR and DCL. Method validation is presented.
authors.affiliation: SC Labormed Pharma S.A., Splaiul Independentei no. 319 E, Bucharest 060044, Romania.
authors.forename: Daniela Iuliana
authors.initials: DI
authors.lastname: Sora
authors.forename: Stefan
authors.initials: S
authors.lastname: Udrescu
authors.forename: Victor
authors.initials: V
authors.lastname: David
authors.forename: Andrei
authors.initials: A
authors.lastname: Medvedovici
mesh_terms: D000284:Administration, Oral; D000293:Adolescent; D000328:Adult; D002851:Chromatography, High Pressure Liquid / Q000295:instrumentation* / Q000379:methods; D004355:Drug Stability; D005260:Female; D039563:Histamine H1 Antagonists, Non-Sedating / Q000097:blood* / Q000737:chemistry; D006801:Humans; D017336:Loratadine / Q000008:administration & dosage / Q000031:analogs & derivatives / Q000097:blood* / Q000737:chemistry; D008297:Male; D015394:Molecular Structure; D010880:Piperidines / Q000008:administration & dosage / Q000097:blood* / Q000737:chemistry; D011725:Pyridines / Q000008:administration & dosage / Q000097:blood* / Q000737:chemistry; D012015:Reference Standards; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013050:Spectrometry, Fluorescence / Q000295:instrumentation / Q000379:methods; D013810:Therapeutic Equivalency
chemical_list: D039563:Histamine H1 Antagonists, Non-Sedating; D010880:Piperidines; D011725:Pyridines; D017336:Loratadine; C121345:desloratadine