Reversed‐Phase High‐Performance Liquid Chromatography Tandem Mass Spectrometry Method for Quantification of Zanamivir in Rat Plasma and the Application in a Pharmacokinetics Study

ABSTRACT A RP‐HPLC‐MS/MS method has been developed for the determination of zanamivir in rat plasma in the present study for the first time. The analytes were retained and separated on a C18 column and a triple‐quadrupole mass spectrometry equipped with an electrospray ionization (ESI) source was applied for quantification. Zanamivir could be well retained in the C18 column under the appropriate chromatographic conditions. A solid phase extraction was used to pretreat the plasma. The extraction recovery was above 83% and the matrix effect could be negligible. The method was linear over the concentration ranges of 1.6–3200.0 ng/mL for zanamivir. The precision and accuracy were within the acceptable limits. The lowest limit of quantification (LLOQ) was 1.6 ng/mL. The on‐column sensitivity of the present method was higher than the reported on‐column sensitivity. This simple method was validated and successfully applied to support the pharmacokinetics study after zanamivir was administered to the Sprague‐Dawley rats.