Simultaneous Determination of Koumine and Gelsemine in Human Plasma Using HPLC-UV Assay and Its Clinical Application

Background: Of two main alkaloids extracted from Gelsemium, koumine was shown to be a promising analgesic, while gelsemine proved to be deleterious. Many patients suspected to be poisoned by Gelsemium cannot be timely diagnosed due to the lack of UPLC-MS/MS. Additionally, the concentration of alkaloids in humans has never been reported. The aim of this study was to establish a more economical and accessible method using HPLC-UV for diagnosis and quantitative analysis of Gelsemium poisoning. Methods: Plasma spiked with an internal standard, oxcarbazepine, was prepared with solid-phase extraction. Koumine and gelsemine were separated on a C-18 column using a mobile phase consisting of methanol, water, and di-n-butylamine (58:42:0.01) pumped at a flow rate of 1.00 mL/min. The detection wavelength was set at 263 nm. Plasma concentrations of two different times were determined for the patients. Results: The calibration curves for both monomers possessed good linearity from 0.05-50 mg/L (r=0.9997 and 0.9999, respectively). The extraction recoveries were greater than 88.5 %. Variation for intraday and interday assays of koumine and gelsemine were less than 8.3% and 7.7%, respectively. The concentrations of the two alkaloids were identified in 5 patients with Gelsemium poisoning by using the established method. Conclusion: The established method by using HPLC-UV is applicable for diagnosis and quantitative analysis of Gelsemium poisoning in such cases. TDM of koumine and gelsemine in patients with Gelsemium poisoning may provide additional information for the clinic to improve rescue strategy.