Development and validation of an HPLC assay for fentanyl, alfentanil, and sufentanil in swab samples

A high performance liquid chromatography (HPLC) method for the assay of fentanyl citrate, alfentanil hydrochloride, and sufentanil citrate swab samples was developed and validated in order to control a cleaning procedure. The swabbing procedure involved Super POLX 1200 wipers moistened with water. The assay employed extraction of swabs with water and analysis by isocratic, reversed-phase, HPLC with varying ultraviolet (UV) detection for desired sensitivity, depending on the analyte. The method was shown to be selective and linear from the limits of quantitation (0.10, 0.20, and 0.15 microg/swab for fentanyl citrate, alfentanil, and sufentanil, respectively) to over three times these concentrations. The assay limits (detection levels) per swab area were set at least at 0.2% of the concentrations of the actives in the drug products (0.02, 0.10, and 0.10 microg/swab or approximately 0.03, 0.02, and 0.2% for fentanyl citrate, alfentanil, and sufentanil, respectively). It should be noted that all active concentrations listed in this work were calculated based on the salt form concentration for fentanyl (citrate salt) and the free base forms for alfentanil and sufentanil. No reference standard was available for alfentanil hydrochloride and sufentanil citrate. Drug product was used instead throughout this study.