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Kudrimoti S, Machin J, Arojojoye AS, Awuah SG, Eisenberg R, Fenger C, Maylin G, Lehner AF, Tobin T. Synthesis and characterization of d 5 -barbarin for use in barbarin-related research. Drug Test Anal 2023; 15:42-46. [PMID: 35975356 PMCID: PMC10087961 DOI: 10.1002/dta.3357] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2022] [Revised: 08/12/2022] [Accepted: 08/12/2022] [Indexed: 01/26/2023]
Abstract
Based on structural similarities and equine administration experiments, Barbarin, 5-phenyl-2-oxazolidinethione from Brassicaceae plants, is a possible source of equine urinary identifications of aminorex, (R,S)-5-phenyl-4,5-dihydro-1,3-oxazol-2-amine, an amphetamine-related US Drug Enforcement Administration (DEA) controlled substance considered illegal in sport horses. We now report the synthesis and certification of d5 -barbarin to facilitate research on the relationship between plant barbarin and such aminorex identifications. D5 -barbarin synthesis commenced with production of d5 -2-oxo-2-phenylacetaldehyde oxime (d5 -oxime) from d5 -acetophenone via butylnitrite in an ethoxide/ethanol solution. This d5 -oxime was then reduced with lithium aluminum hydride (LiAlH4 ) to produce the corresponding d5 -2-amino-1-phenylethan-1-ol (d5 -phenylethanolamine). Final ring closure of the d5 -phenylethanolamine was performed by the addition of carbon disulfide (CS2 ) with pyridine. The reaction product was purified by recrystallization and presented as a stable white crystalline powder. Proton NMR spectroscopy revealed a triplet at 5.88 ppm for one proton, a double doublet at 3.71 ppm for one proton, and double doublet at 4.11 ppm for one proton, confirming d5 -barbarin as the product. Further characterization by high resolution mass spectrometry supports the successful synthesis of d5 -barbarin. Purity of the recrystallized product was ascertained by High Performance Liquid Chromatography (HPLC) to be greater than 98%. Together, we have developed the synthesis and full characterization of d5 -barbarin for use as an internal standard in barbarin-related and equine forensic research.
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Affiliation(s)
- Sucheta Kudrimoti
- The Department of Veterinary Science and the Maxwell H. Gluck Equine Research Center and the Department of Toxicology and Cancer Biology, University of Kentucky, Lexington, Kentucky, USA
| | - Jacob Machin
- The Department of Veterinary Science and the Maxwell H. Gluck Equine Research Center and the Department of Toxicology and Cancer Biology, University of Kentucky, Lexington, Kentucky, USA
| | | | - Samuel G Awuah
- Department of Chemistry, University of Kentucky, Lexington, Kentucky, USA.,Center for Pharmaceutical Research and Innovation, College of Pharmacy and Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, Lexington, Kentucky, USA
| | | | - Clara Fenger
- Equine Integrated Medicine, Georgetown, Kentucky, USA
| | - George Maylin
- New York Drug Testing and Research Program, Ithaca, New York, USA
| | - Andreas F Lehner
- Veterinary Diagnostic Lab Section of Toxicology, Michigan State University, Lansing, Michigan, USA
| | - Thomas Tobin
- The Department of Veterinary Science and the Maxwell H. Gluck Equine Research Center and the Department of Toxicology and Cancer Biology, University of Kentucky, Lexington, Kentucky, USA
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Brewer K, Machin J, Maylin G, Fenger C, Morales-Briceño A, Tobin T. Gabapentin, a human therapeutic medication and an environmental substance transferring at trace levels to horses: a case report. Ir Vet J 2022; 75:19. [PMID: 36192810 PMCID: PMC9531455 DOI: 10.1186/s13620-022-00226-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2022] [Accepted: 09/08/2022] [Indexed: 11/10/2022] Open
Abstract
Gabapentin, 1-(Aminomethyl)cyclohexaneacetic acid, MW 171.240, is a frequently prescribed high dose human medication that is also used recreationally. Gabapentin is orally absorbed; the dose can be 3,000 mg/day and it is excreted essentially unchanged in urine. Gabapentin is stable in the environment and routinely detected in urban wastewater. Gabapentin randomly transfers from humans to racing horses and is at times detected at pharmacologically ineffective / trace level concentrations in equine plasma and urine. In Ohio racing between January 2019 and July 2020,18 Gabapentin identifications, all less than 2 ng/ml in plasma, were reported. These identifications were ongoing because the horsemen involved were unable to pin down and therefore avoid the source of these identifications. Given that 44 ng/ml or less is an Irrelevant Plasma Concentration (IPC) of Gabapentin in horses, we proposed a 5 ng/ml plasma interim Screening Limit of Detection for Gabapentin identifications in Ohio racing, and an essentially similar 8 ng/ml plasma Screening Limit of Detection was suggested by a scientific advisor to the Ohio Horse Racing Commission. As such, an analytical Screening Limit of 8 ng /ml in plasma is an appropriate and pharmacologically conservative analytical "cut-off" or Screening Limit of Detection (SLOD) for Gabapentin in equine competitive events to avoid the calling of "positive" identifications on random unavoidable trace level identifications of this widely prescribed human therapeutic medication in equine forensic samples.
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Affiliation(s)
| | - Jacob Machin
- The Maxwell H. Gluck Equine Research Center and Department of Toxicology and Cancer Biology, University of Kentucky, Lexington, Kentucky, 40546, USA
| | - George Maylin
- New York Drug Testing and Research Program, 777 Warren Rd, Ithaca, NY, 14853, USA
| | - Clara Fenger
- Equine Integrated Medicine, 4904 Ironworks Rd., Georgetown, KY, 40324, USA
| | | | - Thomas Tobin
- The Maxwell H. Gluck Equine Research Center and Department of Toxicology and Cancer Biology, University of Kentucky, Lexington, Kentucky, 40546, USA.
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Machin J, Brewer K, Morales-Briceno A, Fenger C, Maylin G, Tobin T. Sporadic worldwide "clusters" of feed driven Zilpaterol identifications in racing horses: a review and analysis. Ir Vet J 2022; 75:11. [PMID: 35568924 PMCID: PMC9107120 DOI: 10.1186/s13620-022-00215-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2021] [Accepted: 03/31/2022] [Indexed: 11/10/2022] Open
Abstract
Zilpaterol is a β2-adrenergic agonist medication approved in certain countries as a cattle feed additive to improve carcass quality. Trace amounts of Zilpaterol can transfer to horse feed, yielding equine urinary "identifications" of Zilpaterol. These "identifications" occur because Zilpaterol is highly bioavailable in horses, resistant to biotransformation and excreted as unchanged Zilpaterol in urine, where it has a 5 day or so terminal half-life.In horses, urinary steady-state concentrations are reached 25 days (5 half-lives) after exposure to contaminated feed. Zilpaterol readily presents in horse urine, yielding clusters of feed related Zilpaterol identifications in racehorses. The first cluster, April 2013, involved 48 racehorses in California; the second cluster, July 2013, involved 15 to 80 racehorses in Hong Kong. The third cluster, March 2019, involved 24 racehorses in Mauritius; this cluster traced to South African feedstuffs, triggering an alert concerning possible Zilpaterol feed contamination in South African racing. The fourth cluster, September/October 2020 involved 18 or so identifications in French racing, reported by the French Laboratories des Courses Hippiques, (LCH), and in July 2021, a fifth cluster of 10 Zilpaterol identifications in South Africa.The regulatory approach to these identifications has been to alert horsemen and feed companies and penalties against horsemen are generally not implemented. Additionally, given their minimal exposure to Zilpaterol, there is little likelihood of Zilpaterol effects on racing performance or adverse health effects for exposed horses.The driving factor in these events is that Zilpaterol is dissolved in molasses for incorporation into cattle feed. Inadvertent incorporation of Zilpaterol containing molasses into horse feed was the source of the California and Hong Kong Zilpaterol identifications. A second factor in the 2019 Mauritius and 2020 French identifications was the sensitivity of testing for Zilpaterol in Mauritius and France, with the French laboratory reportedly testing at a "more sensitive level for Zilpaterol". As of January 1st, 2021, the new FEI Atypical Finding (ATF) policy specifies Zilpaterol as a substance to be treated as an Atypical Finding (ATF), allowing consideration of inadvertent feed contamination in the regulatory evaluation of Zilpaterol identifications.
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Affiliation(s)
- Jacob Machin
- Department of Toxicology and Cancer Biology and the Maxwell H. Gluck Equine Research Center, Dept. of Veterinary Science, University of Kentucky, Lexington, KY, 40546, USA
| | - Kimberly Brewer
- , 15775 Cypress Creek Lane, Wellington, FL, 33414, New Zealand
| | | | - Clara Fenger
- Equine Integrated Medicine, 4904 Ironworks Rd, Georgetown, KY, 40324, USA
| | - George Maylin
- New York Drug Testing and Research Program, 777 Warren Rd Ithaca, New York, NY, 14853, USA
| | - Thomas Tobin
- Department of Toxicology and Cancer Biology and the Maxwell H. Gluck Equine Research Center, Dept. of Veterinary Science, University of Kentucky, Lexington, KY, 40546, USA.
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Brewer K, Machin JJ, Maylin G, Fenger C, Morales-Briceño A, Neidhart MM, Tobin T. Case report: Synephrine, a plant substance yielding classic environmental clusters of hay related identifications in equine urine. Drug Test Anal 2022; 14:774-780. [PMID: 35088566 DOI: 10.1002/dta.3212] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2021] [Revised: 12/06/2021] [Accepted: 12/08/2021] [Indexed: 11/12/2022]
Affiliation(s)
| | - Jacob Joseph Machin
- The Maxwell H. Gluck Equine Research Center and Department of Toxicology and Cancer Biology, University of Kentucky, Lexington, Kentucky, USA
| | - George Maylin
- Director, New York Drug Testing and Research Program, Ithaca, New York, USA
| | - Clara Fenger
- Equine Integrated Medicine, PLC, Georgetown, Kentucky, USA
| | | | | | - Thomas Tobin
- The Maxwell H. Gluck Equine Research Center and Department of Toxicology and Cancer Biology, University of Kentucky, Lexington, Kentucky, USA
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McClure S, Fenger C, Kersh K, Brown B, Maylin G, Duer W, Dirikolu L, Brewer K, Machin J, Tobin T. Dexamethasone serum concentrations after intravenous administration in horses during race training. Comparative Exercise Physiology 2021. [DOI: 10.3920/cep200015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Dexamethasone (DXM) sodium phosphate is a widely used corticosteroid for inflammatory conditions in horses, regulated in racing jurisdictions in the USA by a 0.005 ng/ml serum/plasma threshold. This study seeks to describe serum concentrations of DXM at 48 and 72 h after intravenous administration of 20 mg DXM sodium phosphate over 1 to 5 days, and to identify a possible source of DXM overages. 74 horses (39 Thoroughbreds, 13 Standardbreds, 22 Quarter Horses) in active race training received 20 mg DXM sodium phosphate. Serum was collected before injection, at 48 and 72 h post last injection, and analysed by LC/MS-MS (limit of quantification (LOQ) = 2.5 pg/ml). No differences were identified by ANOVA (P≤0.05) for racing breeds, age, gender or the number of days of DXM sodium phosphate administration, so data were pooled for each time point. The DXM serum concentration at 48 h (mean ± standard deviation, range) was 2.18±1.56 pg/ml (<2.5 to 40 pg/ml). Summary statistics could not be derived for 72 h DXM serum concentration data owing to censored data, but ranged from <2.5 to 95.8 pg/ml. There was one extreme outlier (Tukey) at 48 h, and two extreme outliers at 72 h. A separate study was conducted using sedentary experimental horses to determine the likelihood that positive DXM samples could result from environmental transfer. Urine was collected from a mare 2 to 3 h post administration of 20 mg DXM. Hay with 100 ml of the DXM (17 ng/ml) containing urine was offered to each of six experimental horses and blood was collected at 0, 4, 8, 12, 16, 20 and 24 h. All six horses had plasma DXM concentration above the limit of detection and five of six had plasma DXM concentrations above the LOQ for at least one sample time.
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Affiliation(s)
- S. McClure
- Midwest Equine Surgery and Sports Medicine, 2615 Eastgate Drive, Boone, IA 50036, USA
- Department of Veterinary Clinical Sciences College of Veterinary Medicine, Iowa State University, 1800 Christensen Drive, Ames, IA 50011-1134, USA
| | - C. Fenger
- Equine Integrated Medicine, PLC, 4904 Ironworks Rd., Georgetown, KY 40324, USA
| | - K. Kersh
- Department of Veterinary Clinical Sciences College of Veterinary Medicine, Iowa State University, 1800 Christensen Drive, Ames, IA 50011-1134, USA
| | - B. Brown
- Bradley Brown, private practice, 425 Sacree Rd., Shelbyville, KY 40065, USA
| | - G. Maylin
- New York Drug Testing and Research Program, Morrisville State College, 777 Warren Rd, Ithaca, NY 14853, USA
| | - W. Duer
- Duer Forensic Toxicology LLC., 1621 Gulf Blvd #102, Clearwater, FL 33767-2928, USA
| | - L Dirikolu
- Department of Comparative Biomedical Sciences, School of Veterinary Medicine, Louisiana State University, Skip Bertman Drive, Baton Rouge, LA 70803, USA
| | - K. Brewer
- Kimberly Brewer, private practice, 15775 Cypress Creek Lane, Wellington, FL 33414, USA
| | - J. Machin
- The Maxwell H. Gluck Equine Research Center, University of Kentucky, 1400 Nicholasville Rd, Lexington, KY 40503, USA
| | - T. Tobin
- The Maxwell H. Gluck Equine Research Center, University of Kentucky, 1400 Nicholasville Rd, Lexington, KY 40503, USA
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Machin J, Childers T, Kudrimoti S, Eisenberg R, Fenger C, Hartmann P, Maylin G, Shults T, Tobin T. Synthesis and characterization of barbarin, a possible source of unexplained aminorex identifications in forensic science. Drug Test Anal 2020; 12:1477-1482. [PMID: 32567235 DOI: 10.1002/dta.2883] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2020] [Revised: 05/29/2020] [Accepted: 06/18/2020] [Indexed: 11/07/2022]
Abstract
Aminorex is a US DEA Schedule 1 controlled substance occasionally detected in racing horses. A number of aminorex identifications in sport horses were thought to have been caused by exposure to plant sources of aminorex. Glucobarbarin, found in plants of the Brassicaceae family, has been suggested as a potential proximate chemical source by being metabolized in the plant or the horse to aminorex. In Brassicaceae, glucobarbarin is hydrolyzed by myrosinase to yield barbarin, which serves as an insect repellant and/or attractant and is structurally related to aminorex. The synthesis, purification, and characterization of barbarin is now reported for use as a reference standard in aminorex related research concerning equine urinary identifications of aminorex and also for possible use in equine administration experiments. Synthesis of barbarin was performed via ring closure between phenylethanolamine and carbon disulfide in tetrahydrofuran with the catalyst pyridine under reflux. The reaction yielded a white crystalline substance that was purified and chemically characterized as barbarin for use as a Certified Reference Standard or for studies related to equine aminorex identification.
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Affiliation(s)
- Jacob Machin
- Department of Toxicology and Cancer Biology and the Maxwell H. Gluck Equine Research Center, Department of Veterinary Science, University of Kentucky, Lexington, Kentucky, USA
| | - Taylor Childers
- Department of Toxicology and Cancer Biology and the Maxwell H. Gluck Equine Research Center, Department of Veterinary Science, University of Kentucky, Lexington, Kentucky, USA
| | - Sucheta Kudrimoti
- Department of Toxicology and Cancer Biology and the Maxwell H. Gluck Equine Research Center, Department of Veterinary Science, University of Kentucky, Lexington, Kentucky, USA
| | | | - Clara Fenger
- Equine Integrated Medicine, Georgetown, Kentucky, USA
| | | | - George Maylin
- New York Drug Testing and Research Program, Ithaca, NY, USA
| | - Theodore Shults
- American Association of Medical Review Officers, Durham, NC, USA
| | - Thomas Tobin
- Department of Toxicology and Cancer Biology and the Maxwell H. Gluck Equine Research Center, Department of Veterinary Science, University of Kentucky, Lexington, Kentucky, USA
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Maylin G, Fenger C, Machin J, Kudrimoti S, Eisenberg R, Green J, Tobin T. Aminorex identified in horse urine following consumption of Barbarea vulgaris; a preliminary report. Ir Vet J 2019; 72:15. [PMID: 31890155 PMCID: PMC6929286 DOI: 10.1186/s13620-019-0153-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2019] [Accepted: 11/22/2019] [Indexed: 11/27/2022] Open
Abstract
Background Aminorex, (RS)-5- Phenyl-4,5-dihydro-1,3-oxazol-2-amine, is an amphetamine-like anorectic and in the United States a Drug Enforcement Administration [DEA] Schedule 1 controlled substance. Aminorex in horse urine is usually present as a metabolite of Levamisole, an equine anthelmintic and immune stimulant. Recently, Aminorex identifications have been reported in horse urine with no history or evidence of Levamisole administration. Analysis of the urine samples suggested a botanical source, directing attention to the Brassicaceae plant family, with their contained GlucoBarbarin and Barbarin as possible sources of Aminorex. Since horsepersons face up to a 1 year suspension and a $10,000.00 fine for an Aminorex identification, the existence of natural sources of Aminorex precursors in equine feedstuffs is of importance to both individual horsepersons and the industry worldwide. Results Testing the hypothesis that Brassicaceae plants could give rise to Aminorex identifications in equine urine we botanically identified and harvested flowering Kentucky Barbarea vulgaris, (“Yellow Rocket”) in May 2018 in Kentucky and administered the plant orally to two horses. Analysis of post-administration urine samples yielded Aminorex, showing that consumption of Kentucky Barbarea vulgaris can give rise to Aminorex identifications in equine urine. Conclusions Aminorex has been identified in post administration urine samples from horses fed freshly harvested flowering Kentucky Barbarea vulgaris, colloquially “Yellow Rocket”. These identifications are consistent with occasional low concentration identifications of Aminorex in equine samples submitted for drug testing. The source of these Aminorex identifications is believed to be the chemically related Barbarin, found as its precursor GlucoBarbarin in Kentucky Barbarea vulgaris and related Brassicaceae plants worldwide.
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Affiliation(s)
- George Maylin
- New York Drug Testing and Research Program, 777 Warren Rd, Ithaca, NY 14853 USA
| | - Clara Fenger
- Equine Integrated Medicine, 4904 Ironworks Rd, Georgetown, KY 40324 USA
| | - Jacob Machin
- 3The Maxwell H. Gluck Equine Research Center and Department of Toxicology and Cancer Biology, University of Kentucky, Lexington, KY 40546 USA
| | - Sucheta Kudrimoti
- 3The Maxwell H. Gluck Equine Research Center and Department of Toxicology and Cancer Biology, University of Kentucky, Lexington, KY 40546 USA
| | | | - Jonathan Green
- 5Department of Plant and Soil Sciences, University of Kentucky, Lexington, KY 40546 USA
| | - Thomas Tobin
- 3The Maxwell H. Gluck Equine Research Center and Department of Toxicology and Cancer Biology, University of Kentucky, Lexington, KY 40546 USA
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Machin J, Duer W, Maylin G, Fenger C, Wilson D, Ivey M, Berthold B, Allison S, Tobin T. Variability in plasma concentrations of methylprednisolone 6 days after intrasynovial injection of methylprednisolone acetate in racing horses: A field study. Equine Vet J 2018; 51:343-348. [DOI: 10.1111/evj.13003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2017] [Accepted: 07/29/2018] [Indexed: 11/30/2022]
Affiliation(s)
- J. Machin
- The Maxwell H. Gluck Equine Research Center and Department of Toxicology and Cancer Biology University of Kentucky Lexington Kentucky USA
| | - W. Duer
- Duer Forensic Toxicology, Inc. Isle of Sand Key Clearwater Florida USA
| | - G. Maylin
- New York Drug Testing and Research Program Ithaca New York USA
| | - C. Fenger
- Equine Integrated Medicine PLC Georgetown Kentucky USA
| | - D. Wilson
- Cleveland Equine Clinic LLC Ravenna Ohio USA
| | - M. Ivey
- Equine Sports Medicine and Surgery Weatherford Texas USA
| | - B. Berthold
- Cleveland Equine Clinic LLC Ravenna Ohio USA
| | - S. Allison
- Cleveland Equine Clinic LLC Ravenna Ohio USA
| | - T. Tobin
- The Maxwell H. Gluck Equine Research Center and Department of Toxicology and Cancer Biology University of Kentucky Lexington Kentucky USA
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Guan F, Uboh CE, Soma LR, Maylin G, Jiang Z, Chen J. Confirmatory Analysis of Continuous Erythropoietin Receptor Activator and Erythropoietin Analogues in Equine Plasma by LC−MS for Doping Control. Anal Chem 2010; 82:9074-81. [PMID: 20945883 DOI: 10.1021/ac102031w] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Affiliation(s)
- Fuyu Guan
- School of Veterinary Medicine, University of Pennsylvania, New Bolton Center Campus, 382 West Street Road, Kennett Square, Pennsylvania 19348, United States, Pennsylvania Equine Toxicology and Research Center, West Chester University, West Chester, Pennsylvania 19382, United States, and Equine Drug Testing and Research Program, College of Veterinary Medicine, Cornell University, 925 Warren Drive, Ithaca, New York 14850, United States
| | - Cornelius E. Uboh
- School of Veterinary Medicine, University of Pennsylvania, New Bolton Center Campus, 382 West Street Road, Kennett Square, Pennsylvania 19348, United States, Pennsylvania Equine Toxicology and Research Center, West Chester University, West Chester, Pennsylvania 19382, United States, and Equine Drug Testing and Research Program, College of Veterinary Medicine, Cornell University, 925 Warren Drive, Ithaca, New York 14850, United States
| | - Lawrence R. Soma
- School of Veterinary Medicine, University of Pennsylvania, New Bolton Center Campus, 382 West Street Road, Kennett Square, Pennsylvania 19348, United States, Pennsylvania Equine Toxicology and Research Center, West Chester University, West Chester, Pennsylvania 19382, United States, and Equine Drug Testing and Research Program, College of Veterinary Medicine, Cornell University, 925 Warren Drive, Ithaca, New York 14850, United States
| | - George Maylin
- School of Veterinary Medicine, University of Pennsylvania, New Bolton Center Campus, 382 West Street Road, Kennett Square, Pennsylvania 19348, United States, Pennsylvania Equine Toxicology and Research Center, West Chester University, West Chester, Pennsylvania 19382, United States, and Equine Drug Testing and Research Program, College of Veterinary Medicine, Cornell University, 925 Warren Drive, Ithaca, New York 14850, United States
| | - Zibin Jiang
- School of Veterinary Medicine, University of Pennsylvania, New Bolton Center Campus, 382 West Street Road, Kennett Square, Pennsylvania 19348, United States, Pennsylvania Equine Toxicology and Research Center, West Chester University, West Chester, Pennsylvania 19382, United States, and Equine Drug Testing and Research Program, College of Veterinary Medicine, Cornell University, 925 Warren Drive, Ithaca, New York 14850, United States
| | - Jinwen Chen
- School of Veterinary Medicine, University of Pennsylvania, New Bolton Center Campus, 382 West Street Road, Kennett Square, Pennsylvania 19348, United States, Pennsylvania Equine Toxicology and Research Center, West Chester University, West Chester, Pennsylvania 19382, United States, and Equine Drug Testing and Research Program, College of Veterinary Medicine, Cornell University, 925 Warren Drive, Ithaca, New York 14850, United States
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Steffenrud S, Maylin G. Thermospray liquid chromatography-mass spectrometry of corticosteroids. J Chromatogr 1992; 577:221-7. [PMID: 1400755] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
A high-performance liquid chromatographic method was developed for thermospray mass spectrometric analysis of steroidal hormones. Using a Nova-Pak C18 reversed-phase column and isocratic elution with a solvent comprised of 25 mM ammonium formate in 30% acetonitrile, corticosteroids were separated within 10 min. This solvent also permitted ultraviolet absorbance detection down to 220 nm with low-nanogram sensitivity. The use of acetonitrile was favourable for thermospray mass spectrometric analysis because mass spectra were obtained with a pseudomolecular ion as the base peak. A combination of liquid chromatography, ultraviolet absorbance detection and thermospray mass spectrometry provided a sensitive and reliable method for unequivocal confirmation of the presence of steroidal drugs in equine urine.
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Affiliation(s)
- S Steffenrud
- Analytical Toxicology and Drug Testing, Cornell University, Ithaca, NY 14850
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12
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Meschter CL, Gilbert M, Krook L, Maylin G, Corradino R. The effects of phenylbutazone on the morphology and prostaglandin concentrations of the pyloric mucosa of the equine stomach. Vet Pathol 1990; 27:244-53. [PMID: 2402852 DOI: 10.1177/030098589002700405] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Phenylbutazone, a nonsteroidal anti-inflammatory drug known to produce gastric ulcers, was administered intravenously (13.46 mg/kg body weight) daily to 12 horses. Horses were euthanatized daily after 24, 48, 72, and 96 hours following the initial injection. Eight untreated horses served as controls. Small multifocal pyloric erosions were seen after 24 hours and then progressed in severity over time. The erosions were characterized by sloughing of the surface epithelium, subepithelial bleb formation, necrosis of the lamina propria, degeneration of the walls of subsurface capillaries, and microthrombosis of the capillaries of the pyloric mucosa. Large numbers of neutrophils with abundant fibrin and cellular debris were present at the erosion sites. Eroded pyloric mucosa and adjacent macroscopically intact mucosa were examined ultrastructurally. In both the macroscopically eroded mucosa and multifocally in the adjacent macroscopically uneroded mucosa, there was cellular swelling of the endothelium, pericytes, and smooth muscle cells of arterioles. In capillaries and post-capillary venules, the endothelium ranged from swollen to lysed and necrotic. Extensive extravasation of erythrocytes and edema were seen. These lesions were not seen in the control horses. Phenylbutazone produces a microvascular injury that is associated with the formation of pyloric erosions in horses. The pyloric mucosa of six horses was assayed for prostacyclin and prostaglandin E2 at 48 and 96 hours following the initial injection. There was no statistically significant difference between prostaglandin concentrations in the mucosa of control and treated horses. It was concluded that there was little correlation between pyloric mucosal prostaglandin concentrations and pyloric erosions after 48 hours.
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Affiliation(s)
- C L Meschter
- Department of Pathology and Equine Drug Testing and Toxicology, College of Veterinary Medicine, Cornell University, Ithaca, NY
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Meschter CL, Gilbert M, Krook L, Maylin G, Corradino R. The effects of phenylbutazone on the intestinal mucosa of the horse: a morphological, ultrastructural and biochemical study. Equine Vet J 1990; 22:255-63. [PMID: 2209522 DOI: 10.1111/j.2042-3306.1990.tb04264.x] [Citation(s) in RCA: 51] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Phenylbutazone, a non-steroidal anti-inflammatory drug known to produce intestinal erosions, was administered intravenously (13.46 mg/kg bodyweight) to 12 horses which were killed after 24, 48, 72 and 96 h. Eight untreated horses served as controls. Annular erosions in the duodenum and mucosal necrosis in the colon were seen after 48 h which progressed in severity. The erosions were characterised by sloughing of the surface epithelium, subepithelial cleft and bleb formation, necrosis of the lamina propria, degeneration of the walls of subsurface capillaries and microthrombosis. Large numbers of neutrophils with abundant fibrin and cellular debris were present at the erosion sites. Ultrastructurally, there was swelling of the endothelium of capillaries and small vessels, and of pericyte and smooth muscle cytoplasm in arterioles. In capillaries and post capillary venules, the endothelium ranged from swollen to lysed and necrotic. Extensive extravasation of erythrocytes and oedema were seen. These lesions were not seen in the control horses. Phenylbutazone produces a microvascular injury associated with the formation of duodenal and colonic erosions in horses. The duodenal and colonic mucosa were assayed at 48 and 96 h for prostacyclin and PGE2. There was no statistically significant difference between prostaglandin levels in the mucosa of control and treated horses. It was concluded that there was no correlation between mucosal prostaglandin levels and intestinal erosions after 48 h.
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Affiliation(s)
- C L Meschter
- Department of Pathology and Equine Drug Testing and Toxicology, College of Veterinary Medicine, Cornell University, Ithaca, New York 14853
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Hill T, Carmichael D, Maylin G, Krook L. Track condition and racing injuries in thoroughbred horses. Cornell Vet 1986; 76:361-79. [PMID: 3757519] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
The incidences of fractures and soft tissue injuries during 68397 starts of thoroughbred horses at New York Racing Association tracks were analyzed concerning track condition, dirt and turf tracks, environmental conditions, length of races, location of fractures on the track, and age of horses. It was concluded that the conditions evaluated are of no importance in the occurrence of racing injuries to thoroughbred horses.
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Covey T, Maylin G, Henion J. Quantitative secondary ion monitoring gas chromatography/mass spectrometry of diethylstilbestrol in bovine liver. Biomed Mass Spectrom 1985; 12:274-87. [PMID: 3160405 DOI: 10.1002/bms.1200120606] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
A procedure is described for the extraction of diethylstilbestrol (DES) from animal tissue for quantitative capillary gas chromatography/mass spectrometry (GC/MS). The procedure is based upon use of a strong anion exchange polystyrene divinylbenzene resin for sample purification. The recovery of DES from the resin clean up was 88% in the high parts per trillion (ppt) range. Criteria for identification of DES using selected ion monitoring (SIM) GC/MS are presented. Liquid chromatography/mass spectrometry (LC/MS) was used to investigate altered DES cis/trans ratios observed in biological extracts.
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Abstract
LC/MS has become a routine research tool in some laboratories. Although no single approach to LC/MS presently is without limitations, each approach offers encouraging results and prompts continued improvements. The remaining hurdles appear to be the introduction of total LC effluent into the MS, increased sensitivity, and the ability to analyze higher molecular weight, polar molecules. The micro LC/MS results discussed in this paper offer an opportunity for significantly increased sensitivity by allowing total micro LC effluent introduction into the MS. It remains to be seen whether the development of micro LC column and equipment technology will allow practical micro LC/MS. It may someday provide improved separation of drugs, metabolites, and their conjugates from high levels of endogenous materials in reasonable time periods. Currently, the impressive efficiencies demonstrated for micro LC columns involve mixtures containing low molecular weight solutes that are perhaps more amenable to GC analysis. The analyst routinely involved with problem solving must deal with complex mixtures composed of components with large concentration differences. The future of micro LC, and hence micro LC/MS, will depend upon how well the technique helps solve problems. We believe the future is bright for micro LC/MS. The techniques may require some fine tuning of operating procedures, just as with capillary GC/MS, but certainly the potential for increased efficiency and sensitivity is worth the effort. Currently we are testing a new micro LC/MS DLI probe wherein the exit of the micro column is within 1 cm of the MS ion source [82]. The micro LC column is contained within the DLI probe and should offer the lowest dead volume and the least extracolumn effects yet achieved by LC/MS. Initial testing of this new probe is under way, and experimental results will be reported subsequently. The analytical potential of micro LC/MS is receiving considerable interest. Practical micro LC performance can provide increased capabilities to all types of LC/MS reported to date, and perhaps offer new insight into alternative methods of LC/MS not yet reported. We look forward to learning of these breakthroughs as they become available.
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