Abstract
A selective and sensitive method was developed and validated based on ultra-performance liquid chromatography–tandem mass spectrometry (UPLC–MS/MS). This method was applied to quantify momordin Ic in rat plasma. Chromatographic separation was performed on a Hypersil GOLD HPLC C18 column (150 mm × 4.6 mm, 5 μm) using an isocratic mobile phase of acetonitrile/water (80:20, v/v) at a flow rate of 0.6 mL/min. An electrospray ionization source was applied and operated in negative ion mode; selected reaction monitoring (SRM) mode was used for quantification by monitoring the precursor-to-product ion transitions of m/z 763.4 → m/z 455.3 for momordin Ic, and m/z 649.4 → m/z 487.3 for IS. Calibration curves showed good linearity over the range of 22.0–2200 ng/mL for momordin Ic in rat plasma. The developed method was applied to a pharmacokinetic study of momordin Ic in rats after single intravenous doses at 0.52, 1.56, and 4.67 mg/kg. The elimination half-life (t1/2) values were 1.22 ± 0.39, 1.14 ± 0.10, and 1.83 ± 0.39 h, respectively. The plasma concentration at 2 min (C2min) and area under the curve (AUC) for the intravenous doses of momordin Ic were approximately dose proportional.
Reference standard of momordin Ic (98.3% purity, Fig. 1) was supplied generously from Herbpurify Co.,Ltd. (Chengdu, China).
