title: Patterns of free (unconjugated) buprenorphine, norbuprenorphine, and their glucuronides in urine using liquid chromatography-tandem mass spectrometry.
abstract: Patterns of buprenorphine and metabolites were examined in 1946 positive urine samples analyzed by liquid chromatography-tandem mass spectrometry for free (unconjugated) buprenorphine and norbuprenorphine (quantitative, 2 to 1000 ng/mL) and buprenorphine-glucuronide (B3G) and norbuprenorphine-glucuronide (N3G) (semi-quantitative, 5 to 1000 ng/mL). Two distribution patterns predominated with 49.1% positive for norbuprenorphine, B3G, and N3G and 41.6% positive for buprenorphine, norbuprenorphine, B3G, and N3G. Buprenorphine, positive in 45.5% of samples, was mostly < 5 ng/mL (median 6.1 ng/mL), but 9.8% were > 1000 ng/mL. Norbuprenorphine, B3G, and N3G had semi-Gaussian distributions with medians of 64.7, 108, and 432 ng/mL, respectively. With buprenorphine < 100 ng/mL (767 samples) or ≥ 100 ng/mL (19 quantifiable samples), the respective median metabolic ratios (free norbuprenorphine/free buprenorphine) were 25.0 and 0.15. In 12 retested "> 1000 ng/mL" buprenorphine samples, free buprenorphine was 4160 to 39,400 ng/mL and free naloxone 2140 to 9560 ng/mL. In 87 subsequent samples with buprenorphine < 20 ng/mL, naloxone concentrations were < 50 ng/mL. Concentrations of buprenorphine > 100 ng/mL (particularly with low metabolite concentrations) are suspect of urine adulteration with medication (4% in the database) that can be checked in most cases by concurrent analysis for naloxone.
authors.affiliation: ARUP Laboratories, Inc., Salt Lake City, UT 84108, USA. gwen.mcmillin@aruplab.com
authors.forename: Gwendolyn A
authors.initials: GA
authors.lastname: McMillin
authors.forename: Rebecka
authors.initials: R
authors.lastname: Davis
authors.forename: Heidi
authors.initials: H
authors.lastname: Carlisle
authors.forename: Chantry
authors.initials: C
authors.lastname: Clark
authors.forename: Stephanie J
authors.initials: SJ
authors.lastname: Marin
authors.forename: David E
authors.initials: DE
authors.lastname: Moody
mesh_terms: D002047:Buprenorphine / Q000031:analogs & derivatives* / Q000652:urine*; D002853:Chromatography, Liquid / Q000379:methods*; D020719:Glucuronides / Q000652:urine*; D006801:Humans; D009270:Naloxone / Q000652:urine; D013048:Specimen Handling / Q000379:methods; D053719:Tandem Mass Spectrometry / Q000379:methods*
chemical_list: D020719:Glucuronides; D009270:Naloxone; D002047:Buprenorphine; C043585:norbuprenorphine