A sensitive and specific method using ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) was developed for the determination of levetiracetam (LEV) in plasma of neonates. A plasma aliquot of 50 μl was deproteinized by addition of 500 μl methanol which contained 5 μg/ml UCB 17025 as an internal standard. After centrifugation, 50 μl of supernatant was diluted with 1000 μl of 0.1% formic acid-10 mM ammonium formate in water (pH 3.5) (mobile phase solution A) and 2 μl was injected onto the UPLC-system. Compounds were separated on a Acquity UPLC BEH C18 2.1 mm × 100 mm column using gradient elution with mobile phase solution A and 0.1% formic acid in methanol (mobile phase solution B) with a flow rate of 0.4 ml/min and a total runtime of 4.0 min. LEV and the internal standard were detected using positive ion electrospray ionization followed by tandem mass spectrometry (ESI-MS/MS). The assay allowed quantification of LEV plasma concentrations in the range from 0.5 μg/ml to 150 μg/ml. Inter-assay inaccuracy was within ±2.7% and inter-assay precision was less than 4.5%. Matrix effects were minor: the recovery of LEV was between 97.7% and 100%. The developed method required minimal sample preparation and less plasma sample volume compared to earlier published LC-MS/MS methods. The method was successfully applied in a clinical pharmacokinetic study in which neonates received intravenous administrations of LEV for the treatment of neonatal seizures.

Acquity, Ammonium compounds, Ammonium formate, Centrifugation, Chromatographic analysis, Chromatography, Clinical pharmacokinetics, Drug products, ESI-MS/MS, Electrospray ionization, Formic acid, Gradient elution, High pressure liquid chromatography, Inter-assay precision, Internal standards, Intravenous administration, LC-MS/MS, Levetiracetam, Liquids, Mass spectrometers, Mass spectrometry, Matrix effects, Methanol, Minimal sample, Mobile phase solution, Neonatal seizure, Neonates, Organic acids, Pharmacokinetics, Plasma, Plasma concentration, Plasma samples, Plasmas, Runtimes, Tandem mass spectrometry, UPLC-MS/MS, Ultra performance liquid chromatography, accuracy, ammonium formate, article, case report, centrifugation, controlled study, drug blood level, drug clearance, drug determination, drug distribution, drug elimination, drug half life, elution, etiracetam, formic acid, human, liquid chromatography, methanol, newborn, positive ion electrospray, priority journal, seizure, tandem mass spectrometry, ultra performance liquid chromatography, water
dx.doi.org/10.1016/j.jchromb.2010.01.037, hdl.handle.net/1765/19436
Journal of Chromatography. B, Analytical Technologies in the Biomedical and Life Sciences
Erasmus MC: University Medical Center Rotterdam

Blonk, M.I, van der Nagel, B.C, Smit, L.S, & Mathôt, R.A.A. (2010). Quantification of levetiracetam in plasma of neonates by ultra performance liquid chromatography-tandem mass spectrometry. Journal of Chromatography. B, Analytical Technologies in the Biomedical and Life Sciences, 878(7-8), 675–681. doi:10.1016/j.jchromb.2010.01.037