title: The in vivo glucuronidation of buprenorphine and norbuprenorphine determined by liquid chromatography-electrospray ionization-tandem mass spectrometry.
abstract: The opioid partial agonist medication, buprenorphine (BUP), and its primary metabolite, norbuprenorphine (NBUP), are extensively glucuronidated. Sensitive analytical methods that include determination of buprenorphine-3-glucuronide (BUPG) and norbuprenorphine-3-glucuronide (NBUPG) are needed to more fully understand the metabolism and pharmacokinetics of buprenorphine. A method has now been developed that uses solid-phase extraction followed by liquid chromatography-electrospray ionization-tandem mass spectrometry. BUP-d4, NBUP-d3, and morphine-3-glucuronide-d3 were used as internal standards. The lower limit of quantitation was 0.1 and 0.5 ng/mL for each of the analytes in 1-mL of human plasma and urine, respectively, except for NBUP in urine in which it was 2.5 ng/mL. The analytes were stable under the following conditions: plasma and urine at room temperature, up to 20 hours; plasma and urine at -20 degrees C for 119 and 85 days, respectively; plasma freeze-thaw, up to 3 cycles; processed sample, up to 96 hours at -20 degrees C and up to 48 hours on the autosampler; stock solutions at room temperature and at -20 degrees C, up to 6 hours and 128 days, respectively. In plasma collected from 5 subjects on maintenance daily sublingual doses of 16 mg BUP and 4 mg naloxone, respective 0- to 24-hour areas under the curve were 32, 88, 26, and 316 ng/mL x h for BUP, NBUP, BUPG, and NBUPG. In urine samples respective percent of daily dose excreted in the 24-hour urine were 0.014%, 1.89%, 1.01%, and 7.76%. This method allowed us to determine that NBUPG is a major metabolite present in plasma and urine of BUP. Because urinary elimination is limited ( approximately 11% of daily dose), the role of NBUPG in total clearance of buprenorphine is not yet known.
authors.affiliation: Center for Human Toxicology, Department of Pharmacology and Toxicology, University of Utah, Salt Lake City, UT 84108, USA.
authors.forename: Wei
authors.initials: W
authors.lastname: Huang
authors.forename: David E
authors.initials: DE
authors.lastname: Moody
authors.forename: Elinore F
authors.initials: EF
authors.lastname: McCance-Katz
mesh_terms: D000286:Administration, Sublingual; D002047:Buprenorphine / Q000031:analogs & derivatives* / Q000032:analysis* / Q000097:blood / Q000737:chemistry / Q000652:urine; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D004355:Drug Stability; D006801:Humans; D009292:Narcotic Antagonists / Q000097:blood / Q000493:pharmacokinetics / Q000652:urine; D015203:Reproducibility of Results; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*; D013696:Temperature; D013997:Time Factors
chemical_list: D009292:Narcotic Antagonists; C499393:norbuprenorphine-3-beta-D-glucuronide; C050182:buprenorphine-3-O-glucuronide; D002047:Buprenorphine; C043585:norbuprenorphine