Determination of Sufentanil in Human Plasma Using Ultra-high Performance Liquid Chromatography Coupled with Tandem Mass Spectrometry (UPLC-MS/MS)

Background: Sufentanil, an opioid analgesic, is used as an induction agent for general anesthesia during surgery. Sufentanil is more active than other anesthetics and has a narrow therapeutic range. Therefore, a precise dosage regimen is necessary when administering sufentanil. Objective: This study aimed to develop a bioanalytical method for the determination of sufentanil within the sensitive concentration range more than that in a previous study utilizing protein precipitation (PP) and determine the plasma concentration of sufentanil. Methods: A method for quantitating sufentanil was developed using ultra-high performance liquid chromatography coupled with mass spectrometry (UPLC-MS/MS) and detection by electrospray ionization (ESI). The internal standard was sufentanil-d₅. Chromatographic separation was performed using an Acquity UPLC HSS T3 column (50 × 2.1 mm, 1.8μm) from Waters (Milford, MA, USA). Protein precipitation (PP) was used for sample preparation, and gradient elution was conducted using a mobile phase consisting of 1 mL of 2M ammonium acetate in 99% formic acid in 1 L of water or in 1 L of acetonitrile. The total run time for the analysis was 5 min, and the flow rate was 0.4 mL/min. Results: Standard curves were linear over ranges of 0.025-30ng/mL for sufentanil with a correlation coefficient (r²) greater than 0.9998. The lower limit of quantification (LLOQ) was 0.025ng/mL. The intra- and inter-day accuracies were 97.66%-108.8% and 101.25%-103.17%, respectively, and the precision did not exceed 15% for sufentanil. Conclusion: This study developed a validated, simple, sensitive, and convenient UPLC-MS/MS method for quantifying sufentanil in human plasma. This method was applied to determine sufentanil concentration in the plasma of patients undergoing surgery. The bioanalytical method using PP showed a sufficiently sensitive concentration range. This method could be applied to various pharmacokinetic studies of sufentanil.