Sci Pharm. 2008; 76: 663–671.
A New High-Throughput LC-MS/MS Assay for Therapeutic Level Monitoring of Valproic Acid in Human Plasma
Laurian VLASE 1, Daniela-Saveta POPA * 2, Dana MUNTEAN 1, Sorin LEUCUTA 1
1 Department of Pharmaceutical Technology and Biopharmacy, Faculty of Pharmacy, "Iuliu Hatieganu" University of Medicine and Pharmacy Emil Isac 13, RO-400023, Cluj-Napoca, Romania
2 Department of Toxicology, Faculty of Pharmacy, "Iuliu Hatieganu" University of Medicine and Pharmacy Emil Isac 13, RO-400023, Cluj-Napoca, Romania
* Corresponding author. E-mail: dpopa@umfcluj.ro (D.-S. Popa)
Abstract
A new high-throughput liquid chromatographic tandem mass spectrometric (LC-MS/MS) assay for the quantification of valproic acid in human plasma was developed and validated. The separation was performed on a Zorbax SB-C18 column under isocratic conditions using a 48:52 (v/v) mixture of acetonitrile and 0.1% (v/v) acetic acid in water at 45 °C with a flow rate of 0.8 mL/min. The detection of valproic acid was performed in SIM mode (m/z 143.1). The human plasma samples (0.2 mL) were deproteinized with methanol and aliquots of 2 μL from supernatants obtained after centrifugation were directly injected into the chromatographic system. The method shows a good linearity (r > 0.9972), precision (CV > 7.8 %) and accuracy (bias > 5.7 %) over the range of 5-200 μg/mL plasma. Lower limit of quantification (LLOQ) was 5 μg/mL and the recovery was between 98-106 %. The method is not expensive, it needs a minimum time for plasma sample preparation and has a run-time of 2.4 min for instrument analysis (retention time of valproic acid was 1.8 min). The developed and validated high-throughput method is very simple, rapid and efficient, with wide applications in clinical level monitoring, pharmacokinetics and bioequivalence studies.
Keywords
Valproic acid • LC-MS/MS • Therapeutic drug monitoring • High-throughput assay
Received August 19th, 2008 | Accepted September 29th, 2008 | Published Online October 10th, 2008
