Sufentanil is used as an anesthetic in the surgical process of general anesthesia and tracheal intubation patients, and is also used as a analgesic agent for postoperative pain. Since the concentration of non-binding plasma drugs affects pharmacokinetics clinically, it needs to verify more accurate drug concentrations.

The purpose of this study was to develop optimal analytical method for sufentanil and to determine the plasma concentration of sufentanil in patients.

Quantification method for sufentanil was developed using ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) consisting of an electrospray ionization (ESI) source. The internal standard was sufentanil-d₅. Chromatogram separation was performed using Acquity UPLC HSS T3 column (50 x 2.1mm, 1.8µm) from Waters (Milford, MA, USA). Gradient elution was executed by a mobile phase consisting of ammonium acetate in formic acid in water or in acetonitrile. Total run time for analysis was 5 minutes and flow rate was 0.4 mL/min.  

Standard curves were linear over ranges of 0.025-25 ng/mL for sufentanil with correlation coefficient (r²) greater than 0.9998. The lower limit of quantifications (LLOQs) was 0.025 ng/mL. The intra- and inter-day accuracy were 101.25-103.17% and precision did not exceed 15% for sufentanil. A validated analytical method can determine sufentanil concentrations and also can be used in pharmacokinetic studies.