UPLC-MS/MS Combined with Microdialysis for Determination of Two Active Components of Chuanxiong Rhizoma Extracts in Rat Brain: Application in Pharmacokinetic Study

Chuanxiong Rhizoma (Chuanxiong), a traditional Chinese medicine, has been widely used to treat various nervous and cardiovascular system-related conditions. Its active components, senkyunolide A (SA) and 3-n-butylphthalide (NBP), have been proven effective in treating nervous system diseases. A new method was established based on microdialysis coupled with ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) to estimate the concentrations of these components in brain extracellular fluid. Chromatographic separation was achieved using an Acquity UPLC BEH C8 column (2.1 x 100 mm, 1.7 mu m) with acetonitrile and 0.1% formic acid as mobile phase. The calibration curves of SA and NBP were linear in the concentration ranges of 0.25-100.00 and 0.12-48.00 ng/mL, respectively, with a correlation coefficient above 0.9992. All validation parameters, including intra- and inter-day precision, accuracy, matrix effect and stability, were within the acceptance limits of bioanalytical guidelines. The validated method was successfully applied to study the pharmacokinetics of SA and NBP in rat brain microdialysis after oral administration of Chuanxiong extracts. The results showed that both components penetrated the brain and reached maximum concentrations in the microdialysates of 72.31 and 9.93 ng/mL at 1.50 and 1.58 h, respectively.