Determination of levocetirizine in human plasma by liquid chromatography-electrospray tandem mass spectrometry: application to a bioequivalence study.

Author(s): Morita MR, Berton D, Boldin R, Barros FA, Meurer EC, Amarante AR, Campos DR, Calafatti SA, Pereira R, Abib E Jr, Pedrazolli J Jr

Affiliation(s): Core Clinical Research, 12914-160 Braganca Paulista, SP, Brazil. mrmorita1@yahoo.com.br

Publication date & source: 2008-02-01, J Chromatogr B Analyt Technol Biomed Life Sci., 862(1-2):132-9. Epub 2007 Dec 4.

Publication type: Randomized Controlled Trial; Validation Studies

We describe a liquid chromatography-tandem mass spectrometric method (LC-MS/MS) for levocetirizine quantification (I) in human plasma. Sample preparation was made using a fexofenadine (II) addition as internal standard (IS), liquid-liquid extraction using cold dichloromethane, and dissolving the final extract in acetonitrile. I and II (IS) were injected in a C18 column and the mobile phase composed of acetonitrile:water:formic acid (80.00:19.90:0.10, v/v/v) and monitored using positive electrospray source with tandem mass spectrometry analyses. The selected reaction monitoring (SRM) was set using precursor ion and product ion combinations of m/z 389>201 for I and m/z 502>467 for II. The limit of quantification and the dynamic range achieved were 0.5ng/mL and 0.5-500.0ng/mL. Validation results on linearity, specificity, accuracy, precision and stability, as well as its application to the analysis of plasma samples taken up to 48h after oral administration of 5mg of levocetirizine dichloridrate in healthy volunteers demonstrate its applicability to bioavailability studies.