High-performance Liquid Chromatography (HPLC) is an analytical technique used to separate, identify, and quantify components in a mixture. In equine research, HPLC is employed to analyze various biological samples from horses, such as blood, urine, and tissue, to detect and measure compounds like drugs, metabolites, and nutritional components. This technique is valued for its precision, sensitivity, and ability to handle complex matrices, making it suitable for pharmacokinetic studies, monitoring therapeutic drug levels, and assessing metabolic profiles in horses. The application of HPLC in equine studies provides insights into drug metabolism, nutritional status, and the biochemical effects of different treatments. This page compiles peer-reviewed research studies and scholarly articles that explore the applications, methodologies, and findings of HPLC in the context of equine science.
Knych HK, Steffey EP, McKemie DS.The objective of the current study was to describe the pharmacokinetics of morphine and its metabolites following intravenous administration to the horse. A total of eight horses (two per dose group) received a single intravenous dose of 0.05, 0.1, 0.2, or 0.5 mg/kg morphine. Blood samples were collected up to 72 h postdrug administration, analyzed using LC-MS/MS and pharmacokinetic parameters determined. Behavior, step counts, and gastrointestinal activity were also assessed. The beta and gamma half-life for morphine ranged from 0.675 to 2.09 and 6.70 to 18.1 h, respectively, following admini...
Jacobson GA, Pirie A, Edwards S, Hughes KJ, Rendle DI, Davies NW.Pergolide, an ergot-derived dopamine D2 receptor agonist, is used extensively as an orally administered treatment for pituitary pars intermedia dysfunction (PPID) in horses. One of the barriers associated with pergolide determinations in plasma for pharmacokinetic applications has been the technically demanding requirement for sensitivity. The objective of our work was to develop a simple assay for the determination of pergolide in plasma and demonstrate its potential application in the study of pergolide pharmacokinetics (PK) in horses. A UPLC-MS/MS assay was developed with a simple sample pr...
Li X, Uboh CE, Soma LR, Liu Y, Guan F, Aurand CR, Bell DS, You Y, Chen J, Maylin GA.Cathinone derivatives are new amphetamine-like stimulants that can evade detection when presently available methods are used for doping control. To prevent misuse of these banned substances in racehorses, development of a liquid chromatography/tandem mass spectrometry (LC/MS/MS) method became the impetus for undertaking this study. Methods: Analytes were recovered via liquid-liquid extraction using methyl tert-butyl ether. Analyte separation was achieved on a hydrophilic interaction column using liquid chromatography and mass analysis was performed on a QTRAP mass spectrometer in positive elec...
Richards SL, Cawley AT, Raftery MJ.Dermorphin, a hepta-peptide with potent analgesic properties, is classified as a doping agent in equine racing. Since its discovery, a number of biologically active structural analogs have been synthesized and made commercially available so there is a need for reliable methods of detection. Results: A sensitive detection method was developed for dermorphin and six analogs in equine urine. Peptide enrichment was achieved using weak cation exchange with subsequent separation and detection by nano-UHPLC-MS/MS. Method validation parameters included: specificity, linearity (5-10000 pg/ml), recovery...
Steel R, Timms M, Levina V, Vine J.The Dermorphins are a family of peptides that act as potent agonists of the opioid μ receptor. Originally identified as a seven amino acid peptide on the skin of the South American Phyllomedusa frog, peptide chemists have since developed a large number of Dermorphin variants, many with superior opioid activity to the original peptide. Dermorphins are unique among the peptide opioid agonists as they appear to have a limited ability to cross the blood brain barrier, producing effects on both the central and peripheral nervous systems. It is this ability of Dermorphins to provide central anaesth...
Guedes AG, Knych HK, Soares JH, Brosnan RJ.This study evaluated the pharmacokinetics and physiological effects of tramadol during repeated oral administrations in horses. Nine adult healthy horses were administered tramadol at 5 and 10 mg/kg orally every 12 h for 5 days in a randomized, crossover design with a 3-week washout between treatments. Plasma concentrations of tramadol, O- and N-desmethyltramadol (M1 and M2) were measured using Liquid-Chromatography-Mass Spectrometry at predetermined time points following each tramadol administration. Cardiovascular, respiratory and gastrointestinal physiological variables were monitored an...
Knych HK, Stanley SD.To describe the effects of alpha2 -adrenergic receptor antagonists on the pharmacodynamics of sublingual (SL) detomidine in the horse. Methods: Randomized crossover design. Methods: Nine healthy adult horses with an average age of 7.6 ± 6.5 years. Methods: Four treatment groups were studied: 1) 0.04 mg kg(-1) detomidine SL; 2) 0.04 mg kg(-1) detomidine SL followed 1 hour later by 0.075 mg kg(-1) yohimbine intravenously (IV); 3) 0.04 mg kg(-1) detomidine SL followed 1 hour later by 4 mg kg(-1) tolazoline IV; and 4) 0.04 mg kg(-1) detomidine SL followed 1 hour later by 0.12 m...
In the present study a general screening protocol was developed to detect prohibited substances and metabolites for doping control purposes in equine sports. It was based on the establishment of a unified sample preparation and on the combined implementation of liquid and gas chromatographic MS analysis. The sample pretreatment began with two parallel procedures: enzymatic hydrolysis of sulfate and glucuronide conjugates, and methanolysis of the 17β-sulfate steroid conjugates. The extracts were treated for LC-TOF-MS, GC-HRMS and GC-MS assays. The majority of the prohibited substances were ide...
Hovanessian N, Davis JL, McKenzie HC, Hodgson JL, Hodgson DR, Crisman MV.The purpose of this study was to determine the pharmacokinetics and safety profile of firocoxib in neonatal foals. Seven healthy foals were administered 0.1 mg/kg firocoxib orally q24 h for nine consecutive days, commencing at 36 h of age. Blood was collected for firocoxib analysis using high-pressure liquid chromatography with fluorescence detection at 0 (dose #1 only), 0.25, 0.5, 1, 2, 4, 8, 16, and 24 h after doses 1, 5, and 9. For all other doses (2, 3, 4, 6, 7, and 8), blood was collected immediately prior to the next dose (24 h trough). Elimination samples (36, 48, 72, 96, 120, and 1...
Merl J, Deeg CA, Swadzba ME, Ueffing M, Hauck SM.Most autoimmune diseases are multifactorial diseases and are caused by the immunological reaction against a number of autoantigens. Key for understanding autoimmune pathologies is the knowledge of the targeted autoantigens, both initially and during disease progression. We present an approach for autoantigen identification based on isolation of intact autoantibody-antigen complexes from body fluids. After organic precipitation of high molecular weight proteins and free immunoglobulins, released autoantigens were identified by quantitative label-free liquid chromatography mass spectrometry. We ...
Théon AP, Pusterla N, Magdesian KG, Wittenburg L, Marmulak T, Wilson WD.The efficacy and biosafety of a previously established tolerable dosage of doxorubicin have not been established in horses. Objective: To provide preliminary evidence of the efficacy of doxorubicin in tumor-bearing horses, explore drug pharmacokinetics profile, and estimate period of risk of exposure to drug residues. Methods: Twelve horses with 37 tumors. Methods: Treatment protocol included 6 treatments at 3-week intervals. Eight horses were uniformly treated at a dosage of 70 mg/m(2) and 4 horses received 4 of 6 treatment cycles at 70 mg/m(2) . Clinical signs, tumor responses, and toxicoses...
Heffron B, Taddei L, Benoit M, Negrusz A.The use of nonsteroidal antiinflammatory drugs in racehorses is allowed under most jurisdictions. Furosemide is administered to treat exercise-induced pulmonary hemorrhage. To help distinguish between therapeutic and illegal uses, racing regulatory bodies have set thresholds in serum for several drugs. The method for the simultaneous detection and quantification of furosemide, flunixin, ketoprofen, phenylbutazone and oxyphenbutazone using 500 µL of serum, and liquid extraction using diethyl ether : hexanes : dichloromethane followed by liquid chromatography tandem mass spectrometry quantitati...
Knych HK, Harrison LM, Casbeer HC, McKemie DS.Methylprednisolone acetate (MPA) is commonly administered to performance horses, and therefore, establishing appropriate withdrawal times prior to performance is critical. The objectives of this study were to describe the plasma pharmacokinetics of MPA and time-related urine and synovial fluid concentrations following intra-articular administration to sixteen racing fit adult Thoroughbred horses. Horses received a single intra-articular administration of MPA (100 mg). Blood, urine, and synovial fluid samples were collected prior to and at various times up to 77 days postdrug administration a...
Ferreira-Dias G, Botelho M, Zagrajczuk A, Rebordão MR, Galvão AM, Bravo PP, Piotrowska-Tomala K, Szóstek AZ, Wiczkowski W, Piskula M, Fradinho MJ....Phytoestrogens exist in plants that are present in forages fed to horses. They may compete with 17-β estradiol and influence the estrous cycle. Therefore, the objective was to determine whether coumestrol from clover-mixed pastures is present in mare's plasma after their ingestion (experiment I), and when this phytoestrogen was present in mare's plasma after ingestion (experiment II). The effect of a long-term ingestion of phytoestrogens on estrous cycle disruption was assessed (experiment III; clinical case). Experiment I was carried out in nonpregnant anestrous and cyclic Lusitano mares (n ...
Devine EP, KuKanich B, Beard WL.To determine the pharmacokinetics of morphine after IM administration in a clinical population of horses. Methods: Prospective clinical study. Methods: 77 horses. Methods: Morphine sulfate (0.1 mg/kg [0.045 mg/lb], IM) was administered to horses, and blood samples were obtained at predetermined time points. Plasma morphine concentrations were measured via liquid chromatography and mass spectrometry. In preliminary investigations, samples were obtained from 2 healthy horses at 12 time points (up to 12 hours after drug administration) and analyzed via 2-stage pharmacokinetic analysis. In the cli...
Gray BP, Viljanto M, Bright J, Pearce C, Maynard S.The detection of the abuse of anabolic steroids in equine sport is complicated by the endogenous nature of some of the abused steroids, such as testosterone and nandrolone. These steroids are commonly administered as intramuscular injections of esterified forms of the steroid, which prolongs their effects and improves bioavailability over oral dosing. The successful detection of an intact anabolic steroid ester therefore provides unequivocal proof of an illegal administration, as esterified forms are not found endogenously. Detection of intact anabolic steroid esters is possible in plasma samp...
Wang CC, Hartmann-Fischbach P, Krueger TR, Wells TL, Feineman AR, Compton JC.Dermorphin and HYP(6) -dermorphin are hepta-peptides and natural opioids originally isolated from the skin of South American frogs. They are more potent than morphine but less likely to produce drug tolerance and addiction. These properties make them ideal candidates for the doping of racehorses to enhance performance during competition. Dermorphin was recently classified as a Class I drug by Racing Commissioners International (RCI), indicating that it is a banned substance in equine athletes. To enforce this ban, a fast and sensitive method was developed for dermorphin and HYP(6)-dermorphin a...
Guan F, Uboh CE, Soma LR, Robinson M, Maylin GA, Li X.Dermorphin is a unique opioid peptide that is 30-40 times more potent than morphine. It was misused and went undetected in horse racing until 2011 when intelligence obtained from a few North American race tracks suggested its use. To prevent such misuse, a reliable analytical method became necessary for detection and identification of dermorphin in post-race horse samples. This paper describes the first liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for such a purpose. Equine plasma and urine samples were pre-treated with ethylenediamine tetra-acetic acid and urea prior to so...
Knych HK, Vidal MA, Casbeer HC, McKemie DS.The use of triamcinolone acetonide (TA) in performance horses necessitates establishing appropriate withdrawal times prior to performance. Objective: To describe the plasma pharmacokinetics of TA and time-related urine and synovial fluid concentrations following i.m. and intra-articular administration to exercised Thoroughbred horses. Methods: Block design. Methods: Twelve racing fit adult Thoroughbred horses received a single i.m. administration of TA (0.1 mg/kg bwt). After an appropriate washout period, the same horses then received a single intra-articular TA administration (9 mg) into the ...
Nieto JE, Maher O, Stanley SD, Knych HK, Snyder JR.To determine the pharmacokinetics, pharmacodynamics, and safety of zoledronic acid in horses. Methods: 8 healthy horses. Methods: A single dose of zoledronic acid (0.057 mg/kg, IV) was administered during a 30-minute period. Venous blood was collected at several time points. Zoledronic acid concentration in plasma was measured by liquid chromatography-tandem mass spectrometry, and pertinent pharmacokinetic parameters were determined. Plasma was analyzed for total calcium, BUN, and creatinine concentrations and a marker for bone resorption (C-terminal telopeptides of type I collagen). Results: ...
Friebe M, Schumacher S, Stahl J, Kietzmann M.This study investigated synovial concentrations of acetylsalicylic acid (ASA) and its metabolite salicylic acid (SA) in the equine fetlock joint following systemic administration of ASA. Salicylates were chosen because SA is the only nonsteroidal anti-inflammatory drug for which threshold levels exist for plasma and urine in equine sports. To avoid animal experiments, the study was conducted using an ex vivo model of the isolated perfused equine distal limb in combination with plasma concentrations obtained from literature.Salicylate concentrations in the joint were determined using microdialy...
Uniacke-Lowe T, Chevalier F, Hem S, Fox PF, Mulvihill DM.Rennet-induced coagulation of bovine milk is a complex mechanism in which chymosin specifically hydrolyzes κ-casein, the protein responsible for the stability of the casein micelle. In equine milk, this mechanism is still unclear, and the protein targets of chymosin are unknown. To reveal the proteins involved, the rennetability of equine milk by calf chymosin was examined using gel-free and gel-based proteomic analysis and compared to bovine milk. RP-HPLC analysis of bovine and equine milks showed the release of several peptides following chymosin incubation. The hydrolyses of equine and bov...
Kaabia Z, Dervilly-Pinel G, Hanganu F, Cesbron N, Bichon E, Popot MA, Bonnaire Y, Le Bizec B.During last decades, the use of natural steroids in racing and food producing animals for doping purposes has been flourishing. The endogenous or exogenous origin of these naturally occurring steroids has since remained a challenge for the different anti-doping laboratories. The administration of these substances to animals is usually made through an intra-muscular pathway with the steroid under its ester form for a higher bioavailability and a longer lasting effect. Detecting these steroid esters would provide an unequivocal proof of an exogenous administration of the considered naturally occ...
Kwok WH, Ho EN, Lau MY, Leung GN, Wong AS, Wan TS.In recent years, there has been an ongoing focus for both human and equine doping control laboratories on developing detection methods to control the misuse of peptide therapeutics. Immunoaffinity purification is a common extraction method to isolate peptides from biological matrices and obtain sufficient detectability in subsequent instrumental analysis. However, monoclonal or polyclonal antibodies for immunoaffinity purification may not be commercially available, and even if available, such antibodies are usually very costly. In our study, a simple mixed-mode anion exchange solid-phase extra...
You Y, Uboh CE, Soma LR, Guan F, Taylor D, Li X, Liu Y, Chen J.A method involving ultra high-performance liquid chromatography-tandem mass spectrometry was developed and validated for the analysis of capsaicin and dihydrocapsaicin in equine plasma. The analytes were recovered from plasma by liquid-liquid extraction using methyl tert-butyl ether and separated on a sub-2 micron column. The mobile phase was composed of 2 mM ammonium formate and methanol. A triple quadrupole mass spectrometer was used to detect the analytes in positive electrospray ionization mode with selected reaction monitoring. The limits of detection, quantification and confirmation for ...
Burton AJ, Giguère S, Warner L, Alhamhoom Y, Arnold RD.Therapeutic drug monitoring in a small number of foals of various ages indicates that the standard adult dose of 6.6 mg/kg bwt q. 24 h for gentamicin is too low and a dose of 12 mg/kg bwt has been proposed. The pharmacokinetics of this dosage in foals and the ages at which this higher dose should be used have not previously been investigated. Objective: To determine the effect of age on the pharmacokinetics of a single 12 mg/kg bwt i.v. dose of gentamicin in foals. Methods: Six healthy foals were given a single i.v. dose of gentamicin at 1-3 days, 2, 4, 8 and 12 weeks of age. Plasma concentrat...
Knych HK, Corado CR, McKemie DS, Steffey EP.Both the potential analgesic effect and the conflicting reports describing tramadol disposition in the horse warrant further study of the pharmacokinetics of tramadol in this species. Objective: To describe the pharmacokinetics of tramadol and its metabolites, O-desmethyltramadol and N-desmethyltramadol, following i.v. administration of 3 doses to the horse. Methods: Nine adult horses received a single i.v. dose of 0.5, 1.5 and 3 mg/kg bwt tramadol. Blood samples were collected prior to and at various times up to 72 h post administration. Plasma samples were analysed using liquid chromatograph...
Manfredi JM, Boyce M, Malone ED, Anderson C, Anderson LB, Trumble TN.Palmar foot pain is frequently treated by steroid injections into the distal interphalangeal joint (DIPJ) in the anticipation that the steroid will diffuse to the navicular bursa and palmar foot structures. The object of this study was to determine if triamcinolone acetonide (TA) would in fact be able to locally diffuse from the DIPJ into the navicular bursa in horses affected by palmar foot pain. Both forelimb DIPJs (nine horses) were injected with 10 mg of TA. Navicular bursa fluid samples, both forelimb and one hind limb (systemic control), were analysed for TA with high-performance liquid ...
Kitaoka Y, Mukai K, Aida H, Hiraga A, Masuda H, Takemasa T, Hatta H.To investigate the effects of high-intensity training (HIT) on carbohydrate and fat metabolism in Thoroughbreds. Methods: 12 Thoroughbreds (3 to 4 years old; 6 males and 6 females). Methods: Horses performed HIT for 18 weeks. They ran at 90% or 110% of maximal oxygen consumption ((V)O(2max)) for 3 minutes (5 d/wk) and were subjected to incremental exercise testing (IET) before and after training. Blood samples were collected during IET, and muscle samples were obtained from the gluteus medius muscle immediately after IET. Phosphofructokinase, citrate synthase, and β-3-hydroxyacyl CoA dehydrog...
Kwok WH, Ho EN, Leung GN, Wong AS, Yue SK, Wan TS.Relaxin (RLX) is a peptide hormone belonging to the relaxin-like peptide family. Relaxin-2 (RLX-2), a heteromeric polypeptide consisting of an A-chain (24 amino acids) and a B-chain (29 amino acids) linked together by two inter-chain disulfide bonds, is the main circulating RLX hormone in human. Due to its ability to dilate blood vessels surrounding the smooth muscles via induction of nitric oxide resulting in the increase of blood and oxygen supplies to the muscles, it may enhance athletic performance and is therefore banned in horseracing, equestrian competitions, and human sports. In order ...
Dosi MCMC, McGorum BC, Kirton RD, Cillán-García E, Mellanby RJ, Keen JA, Hurst EA, Morgan RA.Vitamin D deficiency is common in humans and is increasingly linked to the pathogenesis of a multitude of diseases including obesity and metabolic syndrome. The biology of vitamin D in horses is poorly described; the relative contribution of the diet and skin synthesis to circulating concentrations is unclear and associations with the endocrine disease have not been explored. Objective: To determine the relationship between management, season and endocrine disease and vitamin D status in horses. Methods: Cross-sectional cohort study. Methods: Plasma concentrations of 25-hydroxyvitamin D2 (25(O...
Meucci V, Minunni M, Vanni M, Sgorbini M, Corazza M, Intorre L.Detection of nonsteroidal anti-inflammatory drugs (NSAIDs) in equine plasma is a significant analytical problem in veterinary anti-doping controls. Results: A new HPLC method coupled to selective extraction with molecularly imprinted polymers was developed for the simultaneous determination in equine plasma of the NSAIDs phenylbutazone, flunixin, oxyphenbutazone, ketoprofen and naproxen. The analytical performances of the method have been evaluated both in standard solutions and equine plasma samples. Recovery: Molecularly imprinted polymers solid-phase extraction for all NSAIDs was >94% with ...
Christmann U, Hite RD, Witonsky SG, Elvinger F, Werre SR, Thatcher CD, Tan RH, Buechner-Maxwell VA.Surfactant alterations are described in horses after exercise, anesthesia, and prolonged transport, in horses with recurrent airway obstruction, and in neonatal foals. The effect of horse age or bronchoalveolar lavage fluid (BALF) sample characteristics on surfactant is unknown. Objective: To evaluate surfactant phospholipid composition and function in healthy horses, and to investigate the influence of age and BALF sample characteristics on surfactant. Methods: Seventeen healthy horses 6-25 years of age maintained on pasture year-round. Methods: BALF was collected by standard procedures and w...
Manao G, Camici G, Stefani M, Berti A, Cappugi G, Liguri G, Nassi P, Ramponi G.Acylphosphatase was purified from horse muscle by a new procedure involving an affinity chromatography step and subsequent ion-exchange chromatography. This procedure was considerably milder than the preceding one, gave an overall yield of about 60% of activity and permitted isolation of three molecular forms with acylphosphatase activity. All these enzymatic forms are tightly bound to Sepharose 4B-linked anti-horse muscle acylphosphatase antibodies. Two of these forms (Ho1 and Ho3) are present in larger amounts: Ho1 corresponds to the enzyme purified according to the older procedure; this enz...
Vyniarska A, Ziółkowski H, Madej-Śmiechowska H, Jaroszewski JJ.The aim of this study was to compare the pharmacokinetics of ivermectin and its antiparasitic activity in two horse breeds. Eight Hutsul and 14 Toric horses were administered ivermectin orally at a dose of 0.2 mg/kg body weight. Blood samples were collected for 96 hr, and faecal samples were collected one day before and on days 14 and 21 after drug administration. Ivermectin concentrations in plasma samples were determined by high-performance liquid chromatography. Ivermectin concentration was significantly higher in Toric than in Hutsul horses 90 min after ivermectin administration and was...
Cutler C, Viljanto M, Hincks P, Habershon-Butcher J, Muir T, Biddle S.LGD-4033 is one of a number of selective androgen receptor modulators (SARMs) that are being developed by the pharmaceutical industry to provide the therapeutic benefits of anabolic androgenic steroids, without the less desirable side effects. Though not available therapeutically, SARMs are available for purchase online as supplement products. The potential for performance enhancing effects associated with these products makes them a significant concern with regards to doping control in sports. The purpose of this study was to investigate the metabolism of LGD-4033 in the horse following oral ...
Kwok WH, Leung GN, Wan TS, Curl P, Schiff PJ.Androsta-1,4,6-triene-3,17-dione (ATD) is an irreversible steroidal aromatase inhibitor and is marketed as a supplement. It has been reported to effectively reduce estrogen biosynthesis and significantly increase the levels of endogenous steroids such as dihydrotestosterone and testosterone in human. ATD abuses have been reported in human sports. Its metabolism in human has been studied, and the in vitro metabolic study of ATD in horses has been reported, however, little is known about its biotransformation and elimination in horses. This paper describes the in vitro and in vivo metabolism stu...
Colas C, Garcia P, Popot MA, Bonnaire Y, Bouchonnet S.A method has been developed for the analysis and characterization in equine urine and plasma of iridoid glycosides: harpagide, harpagoside and 8-para-coumaroyl harpagide, which are the main active principles of Harpagophytum, a plant with antiinflammatory properties. The method involves liquid chromatography coupled with positive electrospray ionization mass spectrometry. The addition of sodium or lithium chloride instead of formic acid in the eluting solvent has been studied in order to enhance the signal and to modify the ion's internal energy. Fragmentation pathways and associated patterns ...
Wynn MAA, Ball BA, May J, Esteller-Vico A, Canisso I, Squires E, Troedsson M.The objectives of this study were to compare via liquid chromatography-tandem mass spectrometry (LC-MS/MS) progesterone (P4), 5α-dihydroprogesterone (DHP), allopregnanolone, 3β-hydroxy-5α-pregnan-20-one (3β5P), 20α-hydroxy-5α-pregnan-3-one (20α5P), 5α-pregnan-3β,20α-diol (βα-diol), and 5α-pregnan-3β,20β-diol (ββ-diol) concentrations in plasma of mares with experimentally-induced, ascending placentitis compared to gestationally age-matched control mares. Placentitis was induced via intracervical inoculation of Streptococcus equi spp. zooepidemicus between 260 and 280 days of ge...
Schneiders FI, Noble GK, Boston RC, Dunstan AJ, Sillence MN, McKinney AR.Acepromazine (ACP) is a useful therapeutic drug, but is a prohibited substance in competition horses. The illicit use of ACP is difficult to detect due to its rapid metabolism, so this study investigated the ACP metabolite 2-(1-hydroxyethyl)promazine sulphoxide (HEPS) as a potential forensic marker. Acepromazine maleate, equivalent to 30mg of ACP, was given IV to 12 racing-bred geldings. Blood and urine were collected for 7days post-administration and analysed for ACP and HEPS by liquid chromatography-mass spectrometry (LC-MS). Acepromazine was quantifiable in plasma for up to 3h with little r...
Di Salvo A, Giorgi M, Nannarone S, Lee HK, Corsalini J, Della Rocca G.NSAIDs are often used in horses with colic syndrome during the postoperative period, due to their ability to contrast endotoxemia and to promote an analgesic and anti-inflammatory effect. As the pharmacokinetics of a drug are often modified in unhealthy animals compared to healthy subjects, the aim of this study was to evaluate the pharmacokinetic profile of meloxicam after i.v. administration in horses undergoing laparotomy for colic syndrome. Eight horses received 0.6 mg/kg of meloxicam i.v. towards the end of surgery. Blood samples were taken at scheduled time points during the following 2...
Choi TLS, Kwok KY, Kwok WH, Tsoi YYK, Wong JKY, Wan TSM.Anabolic and androgenic steroids (AAS) are banned substances in both human and equine sports. They are often administered intramuscularly to horses in esterified forms for the purpose of extending their time of action. The authors' laboratory has previously reported an UHPLC/HRMS method using quadrupole-Orbitrap mass spectrometer in full scan and parallel reaction monitoring (PRM) mode for the detection of 48 AAS and/or their esters in horse hair. However, two injections were required due to the long duty cycle time. In this paper, an UHPLC/HRMS method using multiplexed targeted MS mode was de...
Colas C, Garcia P, Popot MA, Bonnaire Y, Bouchonnet S.Solid-phase extraction cartridges among those usually used for screening in horse doping analyses are tested to optimize the extraction of harpagoside (HS), harpagide (HG), and 8-para-coumaroyl harpagide (8PCHG) from plasma and urine. Extracts are analyzed by liquid chromatography coupled with multi-step tandem mass spectrometry. The extraction process retained for plasma applies BondElut PPL cartridges and provides extraction recoveries between 91% and 93%, with RSD values between 8 and 13% at 0.5 ng/mL. Two different procedures are needed to extract analytes from urine. HS and 8PCHG are extr...
Reuter G, Pfeil R, Kamerling JP, Vliegenthart JF, Schauer R.The novel sialic acid 4-O-acetyl-9-O-lactyl-N-acetylneuraminic acid has been identified as a constituent of horse submandibular gland glycoproteins in addition to the already known equine sialic acids, N-acetylneuraminic acid, 4-O-acetyl-N-acetylneuraminic acid, 9-O-acetyl-N-acetylneuraminic acid, 4,9-di-O-acetyl-N-acetylneuraminic acid, N-glycolylneuraminic acid, 4-O-acetyl-N-glycolylneuraminic acid and 9-O-acetyl-N-glycolylneuraminic acid. The structure has been established by combined gas-liquid chromatography-mass spectrometry.
Martins HM, Almeida IF, Camacho CR, Santos SM, Costa JM, Bernardo FM.Fumonisin B1 (FB1), fumonisin B2 (FB2), and overall mycotoxins feed contamination may cause several effects on crops production and animal health. The contamination occurred predominantly in corn and corn-based foods and feeds. Objective: This survey intends to provide the occurrence of fumonisins in swine and equine mixed feeds in Portugal, making an overview from 2007 to 2010. Methods: A total of 363 samples were analyzed, 258 from swine feed and 105 from horse feed with HPLC method. The detection limit was 50 μg/kg for FB1 and 100 μg/kg for FB2. Results: The overall results were 13% of FB...
Zhang XY, Robinson NE, Zhu FX.To evaluate the functional status of neuronal alpha2-adrenoceptors (ARs) and beta2-ARs on ACh release in horses with recurrent airway obstruction (RAO), we examined the effects of the physiological agonists epinephrine (Epi) and norepinephrine (NE) and the beta2-agonists RR- and RR/SS-formoterol on ACh release from airway cholinergic nerves of horses with RAO. Because SS-formoterol, a distomer of the beta2-agonist, increases ACh release from airways of control horses only after the autoinhibitory muscarinic receptors are blocked by atropine, we also tested the hypothesis that if there is an M2...
Dufour P, Courtois J, Seynaeve Y, Peeters S, Le Goff C, Cavalier E, Ponthier J.Steroid concentrations in serum are fluctuating during pregnancy of many mammal species. The current knowledge about endocrinology of gestation is mainly based on immunoassays. However, the lack of specificity of these assays hampers the reliability of the results. In the present work, we developed and validated a methodology associating liquid chromatography (LC) and mass spectrometry (MS) to simultaneously quantify, with high specificity and accuracy, estrone-3-sulfate (E3S), progesterone (PRO), estrone (E1) and estradiol (E2) in serum of two different mammal species. The sample preparation ...
Knych HK, Weiner D, Harrison L, McKemie DS.Intra-articular corticosteroids, such as isoflupredone acetate, are commonly used in the treatment of joint inflammation, especially in performance horses. Following administration in a non-inflamed joints blood concentrations of isoflupredone were low and detectable for only a short period of time post-administration compared to synovial fluid concentrations. For some drugs, inflammation can affect pharmacokinetics, therefore, the goal of the current study was to describe the pharmacokinetics of isoflupredone acetate following intra-articular administration using a model of acute synovitis. S...
Papich MG, Van Camp SD, Cole JA, Whitacre MD.Enrofloxacin was administered i.v. to five adult mares at a dose of 5 mg/kg. After administration, blood and endometrial biopsy samples were collected at regular intervals for 24 h. The plasma and tissue samples were analyzed for enrofloxacin and the metabolite ciprofloxacin by high-pressure liquid chromatography. In plasma, enrofloxacin had a terminal half-life (t(1/2)), volume of distribution (area method), and systemic clearance of 6.7 +/- 2.9 h, 1.9 +/- 0.4 L/kg, and 3.7 +/- 1.4 mL/kg/min, respectively. Ciprofloxacin had a maximum plasma concentration (Cmax) of 0.28 +/- 0.09 microg/mL. In ...
Sander J, Terhardt M, Sander S, Aboling S, Janzen N.Up to now quantification of hypoglycin A in serum and urine in the range of nmols to μmols per liter plus the measurement of accumulated acyl conjugates have been used for the diagnosis of poisoning by fruits or seeds of in humans and animals. A second poison, methylenecyclopropylglycine, however, is known to occur in this material. The objective of our study was to develop and evaluate a method for the quantification of this compound suitable for test materials obtained from animals and man. Methods: Methylenecyclopropylglycine was extracted from serum and urine of a volunteer by a methanoli...
Reiffsteck A, Dehennin L, Scholler R.Estrone, 2-methoxyestrone and estradiol-17 beta have been definitely identified in seminal plasma of man, bull, boar and stallion by high resolution gas chromatography associated with selective monitoring of characteristic ions of suitable derivatives. Quantitative estimations were performed by isotope dilution with deuterated analogues and by monitoring molecular ions of trimethylsilyl ethers of labelled and unlabelled compounds. Concentrations of unconjugated and total estrogens are reported together with the statistical evaluation of accuracy and precision.
Welsch U, Buchheim W, Schumacher U, Schinko I, Patton S.Horse milk fat globules (MFGs) and casein micelles were studied using freeze fracturing, freeze etching and thin-section electron microscopy, as well as lectin histochemistry, gel electrophoresis, and Western blotting. Horse MFGs were found to be relatively small, their average volume-surface diameter being about 2.75 microns. The MFG membrane is composed of three layers: an inner proteinaceous coat occasionally having a paracrystalline substructure, a unit membrane, and a prominent filamentous glycocalyx. The last is rich in glycoconjugates, as revealed by its binding of various lectins. In a...
De Leo M, Giorgi M, Saccomanni G, Manera C, Braca A.Tramadol is a centrally acting analgesic drug that has been used clinically for the last two decades to treat pain in humans. The clinical response of tramadol is strictly correlated to its metabolism, because of the different analgesic activity of its metabolites. O-Desmethyltramadol (M1), its major active metabolite, is 200 times more potent at the micro-receptor than the parent drug. In recent years tramadol has been widely introduced in veterinary medicine but its use has been questioned in some species. The aim of the present study was to develop a new sensible method to detect the whole ...
Hobbs K, Luethy D, Davis J, Mallicote M, Torcivia C, Kulp J, Stefanovski D, Futterman C, Cooper F, van Eps A.Trazodone, a serotonin receptor antagonist and reuptake inhibitor, might be a useful adjunctive treatment in the initial management of horses with acute laminitis if it minimizes ambulation or encourages recumbency. Objective: (1) Evaluate the effects of PO trazodone on ambulatory activity and recumbency in healthy horses; and (2) assess the pharmacokinetics of multiple PO doses of trazodone. Methods: In a randomized cross-over design, 8 healthy horses received placebo or trazodone at 2 doses (2.5 and 7.5 mg/kg) PO q12h for 48 hours with a 14-day washout period between treatments. Forelimb...
Pirhonen A, Valtonen P, Linnala-Kankkunen A, Heiskanen ML, Mäenpää PH.Protamines were extracted from stallion sperm cell nuclei, alkylated with iodoacetamide and separated by reversed-phase high-performance liquid chromatography. Two main components, protamine 1 and protamine 2, were obtained. The latter contains two subspecies, separable by acetic acid-urea-polyacrylamide gel electrophoresis. The primary structure of protamine 2a (St2a) was determined by analysis of fragments obtained from purified protamine 2 peak by thermolysin digestion. The digested peptides were separated by acetic acid-urea gel electrophoresis and, after electroblotting onto a polyvinylid...
Peck K, Mealey KL, Matthews NS, Taylor TS.To determine whether clearance of capacity-limited drugs in horses differs from that in donkeys by comparing the serum disposition of caffeine and its metabolites, theophylline, theobromine, and paraxanthine after i.v. administration of caffeine to horses and donkeys. Methods: 4 healthy horses and 5 healthy donkeys. Methods: Blood samples were collected from each animal at time 0 (before) and 5, 10, 15, 20, 30, and 45 minutes, and 1, 2, 3, 4, 6, 8, 12, 24, 30, 36, 48, 54, 60, 72, and 96 hours after IV administration of a bolus of caffeine. Serum was analyzed in triplicate by high-performance l...
Dimaio Knych HK, Steffey EP, Deuel JL, Shepard RA, Stanley SD.Yohimbine is an alpha 2 adrenergic receptor antagonist used most commonly in veterinary medicine to reverse the effects of the alpha 2 receptor agonists, xylazine and detomidine. Most notably, yohimbine has been shown to counteract the CNS depressant effects of alpha 2 receptor agonists in a number of species. The recent identification of a yohimbine positive urine sample collected from a horse racing in California has led to the investigation of the pharmacokinetics of this compound. Eight healthy adult horses received a single intravenous dose of 0.12 mg/kg yohimbine. Blood samples were co...
Théon AP, Pusterla N, Magdesian KG, Wittenburg L, Marmulak T, Wilson WD.The efficacy and biosafety of a previously established tolerable dosage of doxorubicin have not been established in horses. Objective: To provide preliminary evidence of the efficacy of doxorubicin in tumor-bearing horses, explore drug pharmacokinetics profile, and estimate period of risk of exposure to drug residues. Methods: Twelve horses with 37 tumors. Methods: Treatment protocol included 6 treatments at 3-week intervals. Eight horses were uniformly treated at a dosage of 70 mg/m(2) and 4 horses received 4 of 6 treatment cycles at 70 mg/m(2) . Clinical signs, tumor responses, and toxicoses...
Knych HK, Corado CR, McKemie DS, Steffey EP.Both the potential analgesic effect and the conflicting reports describing tramadol disposition in the horse warrant further study of the pharmacokinetics of tramadol in this species. Objective: To describe the pharmacokinetics of tramadol and its metabolites, O-desmethyltramadol and N-desmethyltramadol, following i.v. administration of 3 doses to the horse. Methods: Nine adult horses received a single i.v. dose of 0.5, 1.5 and 3 mg/kg bwt tramadol. Blood samples were collected prior to and at various times up to 72 h post administration. Plasma samples were analysed using liquid chromatograph...
