Online solid-phase extraction liquid chromatography-electrospray-tandem mass spectrometry analysis of buprenorphine and three metabolites in human urine

An online solid-phase extraction (SPE) liquid chromatography-electrospray tandem mass spectrometry (LC-ESI-MSIMS) method for the determination of buprenorphine (Bup), norbuprenorphine (nBup), buprenorphie-3-beta-D-glucuronide (Bup-3-G) and norbuprenorphie-3-beta-D-glucuronide (nBup-3-G) in human urine was developed and validated. A mixed mode SPE column with both hydrophilic and lipophilic functions was used for online extraction. A C-18 column was employed for LC separation and ESI-MS/MS was utilized for detection. Buprenorphine-D-4 (Bup-D-4) and norbuprenophine-D-3 (nBup-D-3) were used as internal standards for quantitative determination. The extraction, clean-up and analysis procedures were controlled by a fully automated six-port switch valve. Identification and quantification were based on the following transitions: m/z 468 -> 414 for Bup, m/z 414 -> 364 for nBup, m/z 644 -> 468 for Bup-3-G and m/z 590 -> 414 for nBup-3-G, respectively. Good recoveries from 93.6% to 102.2% were measured and satisfactory linear ranges for these analytical compounds were determined. Minimal ion suppression effect (similar to 7% response decrease) was determined. Intra-day and inter-day precision showed coefficients of variance, CV, ranged from 3.3% to 10.1% and 4.4% to 9.8%, respectively. Accuracy ranging from 97.0% to 104.0% was determined. The applicability of this newly developed method was demonstrated by analyzing human urine samples from the patients in Bup treatment program for therapeutic monitoring purpose. (C) 2007 Elsevier B.V. All rights reserved.