Quantification of β‐Elemene by GC–MS and Preliminary Evaluation of Its Relationship With Antitumor Efficacy in Cancer Patients

<b>Objectives:</b> To establish and validate a sensitive and robust gas chromatography-mass spectrometry (GC-MS) method for the quantification of β-elemene in human plasma and assess the correlation between antitumor effect and β-elemene concentration <i>in vivo</i>. <b>Methods:</b> The chromatographic column was HP-5 ms (30 m × 0.25 mm, 0.25 μm, Agilent, United States of America). The carrier gas was helium (purity > 99.5%). The flow rate was 1.0 mL/min and the total run time was 11.0 min. The plasma sample was pretreated with protein precipitation plus liquid-liquid extraction. Cancer patients were enrolled and their samples were collected for analysis. <b>Results:</b> Calibration range of β-elemene was 200.0-20,000.0 ng/mL, with correlation coefficients > 0.99. The intra- and interday precision and accuracy were less than 5.8% and within the range of -10.4%-6.6%. The exposure level of β-elemene in the responder group ranged from 278.13 to 11,886.27 ng/mL, with a median of 3568.91 ng/mL, while in the nonresponder group, the range was from 675.92 to 9716.52 ng/mL, with a median of 3351.94 ng/mL. No difference was found in the β-elemene exposure level between the two groups (<i>p</i> > 0.05). <b>Conclusions:</b> This method was effectively developed, validated, and utilized to quantify β-elemene in cancer patients. The initial findings indicated no significant relationship between therapeutic efficacy and the concentration of β-elemene.