Simultaneous separation and determination of 16 testosterone and nandrolone esters in equine plasma using ultra high performance liquid chromatography-tandem mass spectrometry for doping control.

The potential for using testosterone and nandrolone esters in racehorses to boost the biological concentrations of these steroids and enhance athletic performance is very compelling and should be seriously considered in formulating regulatory policies for doping control. In order to regulate the use of these esters in racehorses, a sensitive and validated method is needed. In this paper, we report such a method for simultaneous separation, screening, quantification and confirmation of 16 testosterone and nandrolone esters in equine plasma by ultra high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS).

Analysis of gabapentin in equine plasma with measurement uncertainty estimation by liquid chromatography-tandem mass spectrometry.

Gabapentin (GPT) is an antiepileptic drug that was approved in 1993 for use in the management of neurotrophic pain and as an adjunctive therapy for refractory partial seizure in humans. It is also being tested in veterinary medicine as an adjunctive medication in the treatment of pain due to laminitis, neuropathic, or chronic pain. Gabapentin is readily available by prescription and even on the internet; therefore, it has the potential of being used in racehorses to mask pain.

Detection and confirmation of 60 anabolic and androgenic steroids in equine plasma by liquid chromatography-tandem mass spectrometry with instant library searching.

In 2008, Pennsylvania (PA) became the first State in the USA to ban and enforce the ban on the use of anabolic and androgenic steroids (AAS) in equine athletes by using plasma for analysis. To enforce the ban, a rapid and high-throughput method for analysis of 60 AAS in equine plasma was developed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Analytes were recovered from plasma by liquid-liquid extraction (LLE) using methyl tert-butyl ether, separated on a reversed-phase C₁₈ column and analyzed by electrospray ionization mass spectrometry.

Ultra-performance liquid chromatography/tandem mass spectrometry in high-throughput detection, quantification and confirmation of anabolic steroids in equine plasma.

An ultra-performance liquid chromatography/tandem mass spectrometry (UPLC/MS/MS) method for fast-throughput analysis of eight anabolic and androgenic steroids (AAS) in equine plasma is reported. Analytes were recovered by liquid-liquid extraction using methyl tert-butyl ether, separated on a 1.9 microm C(18) reversed-phase column, and analyzed in positive electrospray ionization mode on a triple quadrupole mass spectrometer with selected reaction monitoring (SRM) and full product ion scans.

Screening, quantification, and confirmation of phenylbutazone and oxyphenbutazone in equine plasma by liquid chromatography-tandem mass spectrometry.

A sensitive liquid chromatographic-tandem mass spectrometric method was developed and validated for screening, quantification, and confirmation of phenylbutazone and oxyphenbutazone in equine plasma. Analytes were recovered from plasma by liquid-liquid extraction followed by separation in a reversed-phase column and identification by mass spectrometry with selected reaction monitoring in negative electrospray ionization mode. Extraction recovery for both analytes was >80%.

Pharmacokinetics and effects of aminorex in horses.

Objective: To investigate the pharmacokinetics and behavioral effects of aminorex administered IV and PO in horses.

Animals: 7 Thoroughbreds.

Procedures: In a cross-over design, aminorex (0.

Biomarkers of alcohol abuse in racehorses by liquid chromatography/tandem mass spectrometry.

A rapid and sensitive method was developed for the screening, quantification and confirmation of ethyl glucuronide (EG) and ethyl sulfate (ES) as biomarkers for alcohol administration to racehorses using liquid chromatography coupled on-line with triple quadrupole tandem mass spectrometry. Urine sample aliquots (0.1 mL) were pre-treated by protein precipitation.

Resolution, quantification and confirmation of betamethasone and dexamethasone in equine plasma by liquid chromatography/tandem mass spectrometry.

This method describes the simultaneous separation, identification, quantification and confirmation of betamethasone (BTM) and dexamethasone (DXM) in equine plasma by liquid chromatography (LC) integrated with multidimensional tandem mass spectrometry. Analytes were directly extracted from equine plasma by methyl tert-butyl ether (MTBE). The residues were reconstituted with sample solvent.

Quantification and confirmation of flunixin in equine plasma by liquid chromatography-quadrupole time-of-flight tandem mass spectrometry.

The method describes quantification and confirmation of flunixin in equine plasma by liquid chromatography-quadrupole time-of-flight mass spectrometry (LC/Q-TOF/MS/MS). Samples were screened by enzyme-linked immunosorbent assay (ELISA) and only those samples presumptively declared positive were subjected to quantification and confirmation for the presence of flunixin by this method. The method is also readily adaptable to instrumental screening for the analyte.

Quantification of clenbuterol in equine plasma, urine and tissue by liquid chromatography coupled on-line with quadrupole time-of-flight mass spectrometry.

Clenbuterol (CBL) is a potent beta(2)-adrenoceptor agonist used for the management of respiratory disorders in the horse. The detection and quantification of CBL can pose a problem due to its potency, the relatively low dose administered to the horse, its slow clearance and low plasma concentrations. Thus, a sensitive method for the quantification and confirmation of CBL in racehorses is required to study its distribution and elimination.