title: Analysis of phenylbutazone residues in horse tissues with and without enzyme-hydrolysis by LC-MS/MS.
abstract: Phenylbutazone (PBZ) is permitted to be used for the treatment of musculoskeletal pain and inflammation in race horses but it is not approved for use in horses destined for human consumption. In a recent study initiated in our laboratory to study the disposition of PBZ and its oxyphenbutazone (OXPBZ) metabolite in equine tissues, we compared the effect of an additional enzymatic hydrolysis step with ß-glucuronidase on the results of the analysis for PBZ without enzymatic hydrolysis. Incurred tissue samples obtained from a female horse dosed with PBZ at 8.8 mg/kg for 3 days and sacrificed 6 days following the last administration were used for this study. Liver, kidney, and muscle tissues were collected, extracted, cleaned up on a silica-based solid-phase extraction (SPE) preceded by a weak-anion exchange SPE and analyzed with our in-house validated liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for PBZ and OXPBZ. Addition of the hydrolysis step resulted in a significant increase in recovery of both PBZ and OXPBZ residues. © 2016 Her Majesty the Queen in Right of Canada. Drug Testing and Analysis © 2016 John Wiley & Sons, Ltd.
authors.affiliation: CFIA Saskatoon Laboratory, 116 Veterinary Road, Saskatoon, SK., Canada S7N 2R3.
authors.forename: Joe O
authors.initials: JO
authors.lastname: Boison
authors.affiliation: Department of Veterinary Biomedical Sciences, Western College of Veterinary Medicine, Saskatoon, SK, Canada S7N 5B4.
authors.forename: Trisha
authors.initials: T
authors.lastname: Dowling
authors.affiliation: Department of Biomedical Sciences, Ontario Veterinary College, University of Guelph, ON, Canada N1G 2W1.
authors.forename: Ron
authors.initials: R
authors.lastname: Johnson
authors.affiliation: CFIA Saskatoon Laboratory, 116 Veterinary Road, Saskatoon, SK., Canada S7N 2R3.
authors.forename: Jana
authors.initials: J
authors.lastname: Kinar
mesh_terms: D000818:Animals; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000032:analysis* / Q000378:metabolism / Q000493:pharmacokinetics; D002853:Chromatography, Liquid / Q000379:methods; D004350:Drug Residues / Q000032:analysis* / Q000378:metabolism / Q000493:pharmacokinetics; D005260:Female; D005506:Food Contamination / Q000032:analysis; D064088:Hazard Analysis and Critical Control Points / Q000379:methods; D006736:Horses / Q000378:metabolism*; D006801:Humans; D006868:Hydrolysis; D007668:Kidney / Q000737:chemistry / Q000378:metabolism; D008099:Liver / Q000737:chemistry / Q000378:metabolism; D009132:Muscles / Q000737:chemistry / Q000378:metabolism; D010113:Oxyphenbutazone / Q000032:analysis* / Q000378:metabolism / Q000493:pharmacokinetics; D010653:Phenylbutazone / Q000032:analysis* / Q000378:metabolism / Q000493:pharmacokinetics; D052616:Solid Phase Extraction / Q000379:methods; D053719:Tandem Mass Spectrometry / Q000379:methods*; D014018:Tissue Distribution
chemical_list: D000894:Anti-Inflammatory Agents, Non-Steroidal; D010653:Phenylbutazone; D010113:Oxyphenbutazone
keywords: LC-MS/MS; enzyme hydrolysis; equine liver; kidney; muscle tissue; oxyphenbutazone; phenylbutazone