Determination of curdione in rabbit plasma by liquid chromatography mass spectrometry

A sensitive and selective liquid chromatography mass spectrometry method for determination of curdione in rabbit plasma was developed. After addition of tramadol as internal standard (IS), protein precipitation by acetonitrile was used for sample preparation. Chromatographic separation was achieved on a Zorbax SB-C₁₈ (2.1 × 50 mm, 3.5 µm) column with acetonitrile-0.1% formic acid as mobile phase with gradient elution. An electrospray ionization source was applied and operated in positive-ion mode; selective ion monitoring was used for quantification using target fragment ions m/z 237 for curdione and m/z 264 for the IS. Calibration plots were linear over the range of 20-4000 ng/mL for curdione in plasma. The lower limit of quantification for curdione was 20 ng/mL. Mean recovery of curdione from plasma was in the range 94.3-98.4%. The RSD of intra-day and inter-day precision were both less than 9%. This method is simple and sensitive enough to be used in pharmacokinetic research for the determination of curdione in rabbit plasma.