High-performance liquid chromatography with electrochemical detection for the determination of 7-monohydroxyethylrutoside in plasma

MonoHER (7-monohydroxyethyl rutoside) is a semisynthetic flavonoid, which c an be used as a modulator for doxorubicin-induced cardiotoxicity. To study the pharmacokinetics of monoHER in mice and human an HPLC procedure was dev eloped to measure the level of monoHER in plasma. After extraction of monoH ER with methanol, the supernatant was equally diluted (v/v) with 25 mM phos phate buffer (pH 3.33). This solution was analysed by HPLC, using a reverse d-phase ODS column, with a mobile phase consisting of 49% methanol and 51% of an aqueous solution containing 10 mM sodium dihydrogen phosphate (pH 3.4 ), 10 mM acetic acid and 36 muM EDTA. The retention time of monoHER was abo ut 5.2 min. The lower limit of quantification of monoHER was set at 0.3 muM and the calibration line was linear up to 75 muM. The within-day accuracy and precision of the quality control samples (0.45, 1.0, 10 and 40 muM) wer e better than 15 and 13%, respectively. The between-day accuracy and precis ion were less than 3, 20%, respectively. The recovery of monoHER (using qua lity control concentrations) was concentration independent and ranged from 90.5 to 95.3% except for the lowest quality control, 0.45 muM, Of which the recovery was 85%. The concentration of monoHER in plasma decreased with 10 % when stored at -80 degreesC for one month and with 20% when stored at -20 degreesC for 3 weeks. The repeated injection of monoHER in aliquots of 10 muM, stored in the autosampler tray (4 degreesC), showed a consistent decre ase during a run: 15% over 24 h. To compensate for this decrease, sample du plicates were analysed in a mirror image sequence. (C) 2001 Elsevier Scienc e B.V. All rights reserved.