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Rumpler M.J.,University of Florida | Colahan P.,University of Florida | Sams R.A.,University of Florida | Sams R.A.,HFL Sport Science Inc.
Journal of Veterinary Pharmacology and Therapeutics | Year: 2014

The disposition of plasma glycopyrrolate (GLY) is characterized by a three-compartment pharmacokinetic model after a 1-mg bolus intravenous dose to Standardbred horses. The median (range) plasma clearance (Clp), volume of distribution of the central compartment (V1), volume of distribution at steady-state (Vss), and area under the plasma concentration-time curve (AUC0-inf) were 16.7 (13.6-21.7) mL/min/kg, 0.167 (0.103-0.215) L/kg, 3.69 (0.640-38.73) L/kg, and 2.58 (2.28-2.88) ng*h/mL, respectively. Renal clearance of GLY was characterized by a median (range) of 2.65 (1.92-3.59) mL/min/kg and represented approximately 11.3-24.7% of the total plasma clearance. As a result of these studies, we conclude that the majority of GLY is cleared through hepatic mechanisms because of the limited extent of renal clearance of GLY and absence of plasma esterase activity on GLY metabolism. Although the disposition of GLY after intravenous administration to Standardbred horses was similar to that in Thoroughbred horses, differences in some pharmacokinetic parameter estimates were evident. Such differences could be attributed to breed differences or study conditions. The research could provide valuable data to support regulatory guidelines for GLY in Standardbred horses. © 2013 John Wiley & Sons Ltd. Source

Rumpler M.J.,University of Florida | Sams R.A.,University of Florida | Sams R.A.,HFL Sport Science Inc. | Colahan P.,University of Florida
Journal of Chromatography B: Analytical Technologies in the Biomedical and Life Sciences | Year: 2012

We describe a validated, rapid, sensitive, and specific UHPLC-MS/MS method to detect and quantify glycopyrrolate in 0.5. mL of horse urine. Further, we investigated the elimination of glycopyrrolate in urine after both intravenous and oral administration of clinically relevant doses to Thoroughbred horses. Quantification was performed by weighted, linear regression analysis using a deuterated analogue of glycopyrrolate as internal standard (IS). The method was characterized by a linear range of 5-2500. pg/mL, a lower limit of quantification of 5. pg/mL and a limit of detection of 1. pg/mL. The intra and inter-batch imprecisions were <10% RSD and accuracy of the method ranged between 94 and 104%. Glycopyrrolate remained detectable in urine samples collected through 168. h after intravenous administration and through 24. h after oral administration. Analytical method validation requirements for linearity, specificity, precision, accuracy, stability, dilution integrity, matrix effect, and ruggedness have been fulfilled. The urine method described in this report is simple and efficient and is the first reported method with sufficient sensitivity, accuracy, and precision to regulate the use of glycopyrrolate in urine samples collected more than one day after dosing of horses. Urine to plasma glycopyrrolate concentration ratios were calculated and were approximately 100:1 in samples collected from 24. h through the end of sample collection. © 2012 Elsevier B.V. Source

Hudson S.,HFL Sport Science Inc. | Ramsey J.,St Georges, University of London
Drug Testing and Analysis | Year: 2011

In late 2008, several synthetic cannabinoids were detected in herbal smoking mixtures. Typical of these products were 'Spice Gold', 'Spice Silver' and 'Yucatan Fire', but many other products have since appeared. The analytes detected, such as JWH-018 and CP47,497 are experimental compounds, some of which were never designed for human use. Both scientific and anecdotal evidence suggest that these compounds are more potent than traditional cannabis and are being widely used. As a result, authorities around the world are now beginning to control them by either naming individual compounds or using generic legislation. This, however, is easier said than done as the synthetic cannabinoids detected are constantly changing in attempts by manufacturers to evade legislation. This paper includes background information in the style of a brief monograph, as an aid to rapidly understanding the pharmacological aspects of these compounds in the forensic context, and then presents a comprehensive set of data, obtained from analysis of purchased products by gas chromatography-mass spectrometry (GC-MS) and liquid chromatography-tandem mass spectrometry (LC-MS/MS). © 2011 John Wiley & Sons, Ltd. Source

Fenwick S.J.,HFL Sport Science Inc. | Scarth J.P.,HFL Sport Science Inc.
Drug Testing and Analysis | Year: 2011

Within horseracing, the detection of prohibited substance doping often requires urine analysis; hence, it is necessary to understand the metabolism of the drugs in question. Here, the previously unknown equine metabolism of eight sedatives is reported in order to provide information on target metabolites for use in doping control. Phase I metabolite information was provided by incubation with equine liver S9 fraction. In vitro techniques were chosen in order to reduce the ethical and financial issues surrounding the study of so many compounds, none of which are licensed for use in horses in the UK. Several metabolites of each drug were identified using liquid chromatography-high resolution mass spectrometric (LC-HRMS) analysis on an LTQ-Orbitrap. Further structural information was obtained by tandem mass spectrometry (MS/MS) analysis; allowing postulation of the structure of some of the most abundant in vitro metabolites. The most abundant metabolites of alpidem, etifoxine, indiplon, tiletamine, zaleplon, zolazepam, zolpidem, and zopiclone related to hydroxylation/N-oxidation, deethylation, demethylation, deethylation, hydroxylation/N-oxidation, demethylation, hydroxylation/N-oxidation and hydroxylation/N-oxidation, respectively. In many cases, further work would be required to fully elucidate the precise positioning of the functional groups involved. The results of this study provide metabolite information that can be used to enhance equine anti-doping screening methods. However, the in vitro metabolites identified are at present only a prediction of those that may occur in vivo. In the future, any positive findings of these drugs and/or their metabolites in horse urine samples could help validate these findings and/or refine the choice of target metabolites. © 2011 John Wiley & Sons, Ltd. Source

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