Simultaneous quantification of naproxcinod and its active metabolite naproxen in rat plasma using LC-MS/MS: application to a pharmacokinetic study

J Chromatogr B Analyt Technol Biomed Life Sci. 2015 Jan 26:978-979:157-62. doi: 10.1016/j.jchromb.2014.12.001. Epub 2014 Dec 11.

Abstract

In this study, a liquid chromatography-tandem mass spectrometry method was developed and validated to simultaneously determine naproxcinod and naproxen concentrations in rat plasma for the first time. Plasma samples were prepared by simple one-step extraction with methanol for protein precipitation using only 50 μL plasma. Separation was performed on a Synergi Fusion-RP C18 column with a run time of 4 min. Naproxcinod, naproxen and internal standard concentrations were detected in the positive ion mode using multiple reaction monitoring (MRM) of the transitions at m/z 348.2→302.2, 231.1→185.1 and 271.2→203.1, respectively. The calibration curves were linear, with all correlation coefficients being ≥0.9952, in the range of 1.00-400 ng/mL for naproxcinod and 20.0-8000 ng/mL for naproxen. Their accuracy was in the range of -8.1% to 8.7%, and the intra- and inter-day variations were ≤4.53%. The mean extraction recovery of all analytes was more than 93.1% efficient. Stability testing showed that naproxcinod and naproxen remained stable during the whole analytical procedure. After validation, the method was successfully applied to a pharmacokinetic study of naproxcinod and naproxen in rats. The AUC0-∞ of naproxen was 74.6 times larger than that of naproxcinod, which indicated that naproxcinod was rapidly metabolized into naproxen in rats.

Keywords: LC–MS/MS; Naproxcinod; Naproxen; Pharmacokinetic study.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Chromatography, Liquid / methods*
  • Drug Stability
  • Linear Models
  • Male
  • Naproxen / analogs & derivatives*
  • Naproxen / blood*
  • Naproxen / chemistry
  • Naproxen / pharmacokinetics
  • Rats
  • Rats, Sprague-Dawley
  • Reproducibility of Results
  • Sensitivity and Specificity
  • Tandem Mass Spectrometry / methods*

Substances

  • naproxen-n-butyl nitrate
  • Naproxen