Quantification of Nardosinone in Rat Plasma Using Liquid Chromatography–Tandem Mass Spectrometry and Its Pharmacokinetics Application

A rapid, sensitive and high-throughput liquid chromatography-tandem mass spectrometry (LC-MS-MS) method was established and validated to assay the concentration of nardosinone, a main active compound isolated from Nardostachys chinensis, in rat plasma. Plasma samples were processed by protein precipitation with acetonitrile and separated on a Venusil MP-C18 column (50 × 2.1 mm, 5 µm) at an isocratic flow rate of 0.6 mL/min using methanol-0.1% formic acid in water (55 : 45, v/v) as mobile phase, and total run time was 2.5 min. MS-MS detection was accomplished in selected reaction monitoring mode with positive electrospray ionization. The calibration curve was linear over the concentration range of 9.60-320 ng/mL with lower limit of quantification of 9.60 ng/mL. The intra- and inter-day precisions were below 12.3% in terms of relative standard deviation, and the accuracy was within ±9.0% in terms of relative error. Extraction recovery, matrix effect and stability were also satisfactory in rat plasma. The developed method was successfully applied to a pharmacokinetic study of nardosinone following an intravenous injection at a dose of 1.04 mg/kg to Sprague-Dawley rats.