Quantification of nortriptyline in plasma by HPLC and fluorescence detection

A simple, sensitive and specific high-performance liquid chromatography method has been developed for the determination of nortriptyline (NT) in plasma samples. The assay involved derivatization with 9H-fluoren-9-ylmethyl chloroformate (Fmoc-Cl) and isocratic reversed-phase (C-18) chromatography with fluorescence detection. The developed method required only 100 mu l of plasma sample, deproteinized and derivatized in one step. Calibration curves were lineal over the concentration range of 5-5000 ng/ml. The derivatization reaction was performed at room temperature in 20 min and the obtained NT derivative was stable for at least 48 h at room temperature. The within-day and between-day relative standard deviation was below 8%. The limit of detection (LOD) was 2 ng/ml, and the lower limit of quantification (LLOQ) was established at 10 ng/ml. The method was applied on plasma collected from rats, at different time intervals, after intravenous administration of 0.5 mg of NT. (C) 2010 Elsevier B.V. All rights reserved.