Hollow fiber liquid-phase microextraction combined with ultra-high performance liquid chromatography-tandem mass spectrometry for the simultaneous determination of naloxone, buprenorphine and norbuprenorphine in human plasma

A hollow fiber liquid phase microextraction (HF-LPME) combined with ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method was developed for the extraction and determination of naloxone (NLX), buprenorphine (BP) and its major metabolite norbuprenorphine (NBP) in human plasma. The optimum extraction conditions of HF-LPME were: the porous of polyvinylidene fluoride (PVDF) hollow fiber was full of component solvent (1-octanol/chloroform/toluene, 2/4/4), the pH of donor phase was 8.7, the extraction time was 30 min and stirring speed was 1000 revolutions per minute (rpm). The UHPLC-MS/MS method was performed with Waters ACQUITY UPLCTM BEH C18, 50 mm x 2.1 mm, 1.7 mu m, using methanol-0.2%formic acid as mobile phase with a gradient elution at a flow rate of 0.25 mL/min. The target compounds were detected under a tandem quadrupole mass spectrometer in positive electrospray ionization (ESI) mode, then analyzed in multiple reaction monitoring (MRM) mode and the isotope internal standard method was used for quantification. The results showed that linearities were in the range of 0.1-25 ng/mL (R > 0.996). The limits of detection (LOD) of BP/NBP/NLX were 0.05/0.05/0.025 ng/mL and the limits of quantitation (LOQ) of BP/NBP/NLX were 0.1/0.1/0.05 ng/mL, respectively. The spiked recoveries were in the range of 92.1-106.0% with relative standard deviation (RSD) values were less than 15%. This method was simple, inexpensive, sensitive and has been successfully used to quantify plasma samples from patients included in a clinical pharmacogenetic study. (C) 2014 Published by Elsevier B.V.