Simultaneous quantification of multiple volatile active components in rat plasma using a headspace-solid phase dynamic extraction method coupled to gas chromatography-tandem mass spectroscopy: application in a pharmacokinetic study of Longhu Rendan pills

Abstract

Longhu Rendan pills (LRPs), a traditional Chinese over-the-counter medicine, have been used for the prevention and treatment of heatstroke and motion sickness. A sensitive, specific, and accurate headspace-solid-phase dynamic extraction method coupled to gas chromatography-tandem mass spectrometry (HS-SPDE-GC-MS/MS) was developed and validated for the investigation of the pharmacokinetic properties of L-menthol, borneol, isoborneol, and the metabolite camphor in rats after oral administration of LRPs. Target compounds were extracted using an SPDE needle device coated with a polydimethylsiloxane solid phase. Detection of components was achieved by GC-MS/MS in multiple reaction monitoring mode. This method was successfully applied in the evaluation of the pharmacokinetics of components and a metabolite of LRPs after a single intragastric administration of a 0.92 g kg⁻¹ dose to rats. Pharmacokinetic parameters were calculated from the plasma concentration–time data. C_max values of L-menthol, borneol, isoborneol, and camphor in rat plasma were determined to be 876 ± 341, 268 ± 149, 158 ± 91, and 126 ± 56 ng mL⁻¹, respectively, and the AUC_0–t values were measured as 876 ± 259, 408 ± 121, 140 ± 50, and 401 ± 35 ng h mL⁻¹, respectively. These results provide useful information on the effective components of LRPs.