Validated ion pair liquid chromatography/fluorescence detection method for assessing the variability of the loratadine metabolism occurring in bioequivalence studies

• Published in: Biomedical chromatography Vol. 21; no. 10; pp. 1023 - 1029
• Main Authors: Sora, Daniela Iuliana, Udrescu, Stefan, David, Victor, Medvedovici, Andrei
• Format: Journal Article
• Language: English
• Published: Chichester, UK John Wiley & Sons, Ltd 01.10.2007
• Subjects: Administration, Oral; Adolescent; Adult; Chromatography, High Pressure Liquid - instrumentation; Chromatography, High Pressure Liquid - methods; descarboethoxyloratadine; Drug Stability; Female; fluorescence detection; Histamine H1 Antagonists, Non-Sedating - blood; Histamine H1 Antagonists, Non-Sedating - chemistry; Humans; ion pair separation mechanism; liquid-liquid extraction; loratadine; Loratadine - administration & dosage; Loratadine - analogs & derivatives; Loratadine - blood; Loratadine - chemistry; Male; metabolic inter/intra subject variability; method validation; Molecular Structure; Piperidines - administration & dosage; Piperidines - blood; Piperidines - chemistry; Pyridines - administration & dosage; Pyridines - blood; Pyridines - chemistry; Reference Standards; Reproducibility of Results; Sensitivity and Specificity; Spectrometry, Fluorescence - instrumentation; Spectrometry, Fluorescence - methods; Therapeutic Equivalency
• ISSN: 0269-3879; 1099-0801
• DOI: 10.1002/bmc.845

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® 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 µL). 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. Copyright © 2007 John Wiley & Sons, Ltd.