Urine analysis in horses involves the examination of urine to assess the health and physiological status of the animal. This diagnostic tool provides insights into the renal function, hydration status, and potential presence of systemic diseases. Key parameters evaluated in equine urine analysis include pH, specific gravity, protein levels, glucose, ketones, and the presence of blood or sediment. Variations in these parameters can indicate metabolic disorders, infections, or other health issues. This page compiles peer-reviewed research studies and scholarly articles that explore the methodologies, findings, and clinical implications of urine analysis in equine veterinary practice.
Genetzky RM, Loparco FV, Ledet AE.A 72-hour water deprivation test was performed in 12 horses to determine clinical pathologic changes. Reference values for electrolyte (X) clearance, expressed as a percentage of creatinine clearance (CLCR; %CLCRX), were also determined. A comparison was made between urine concentration measurement techniques. Results of %CLCRX determination in 12 horses before water deprivation were 0.034 +/- 0.095 %CLCRNa, 42.4 +/- 9.8 %CLCRK, 0.352 +/- 0.190 %CLCRCl, and 0.710 +/- 0.250 %CLCRP. During water deprivation, there was individual variation for electrolyte clearances, but Na excretion increased si...
Beaumier PM, Fenwick JD, Stevenson AJ, Weber MP, Young LM.Plasma and urinary levels of salicylic acid were examined in Standardbred mares after administration of various feeds, containing different compositions of hay. In addition, horses were administered acetylsalicylic acid orally and methyl salicylate topically. Elevated salicylic acid levels were observed in horse urine and plasma in animals fed lucerne hay. The plasma and urinary elimination of salicylic acid exhibited a diurnal pattern which was related to the type of feed and the feeding schedule. Within 24 h after oral administration of acetylsalicylic acid, plasma and urine salicylic acid l...
Divers TJ, Whitlock RH, Byars TD, Leitch M, Crowell WA.Six horses had been admitted to the hospital because of illness other than renal failure; diarrhoea, myositis, abdominal pain and/or suspected bacterial sepsis. Hypotension and disseminated intravascular coagulopathy were frequent findings in the horses. Abnormally high serum creatinine concentration and urine specific gravity of less than 1.022 were found in the horses with acute renal failure. Hyponatraemia and hypochloraemia were the most common abnormal electrolyte findings. Pronounced hyperkalaemia was not found. Variable degrees of tubular necrosis were seen in three of the four horses t...
Smith ML, Chapman CB.An acepromazine (ACP) hapten was synthesised, coupled to bovine serum albumin and injected into a horse to produce antibodies to the drug. A competitive ELISA was developed whereby ACP attached to the solid phase via lysozyme competed with free ACP present in phosphate buffered saline, horse serum or horse urine for limiting amounts of antibody. The assay could detect the presence of ACP and, or, some of its metabolites in horse urine for at least 25 hours after intravenous injection of 0.1 mg kg-1 ACP maleate, but because of non-specific interference, horse serum could not be used. As little ...
Slais K, Nielen MW, Brinkman UA, Frei RW.Amphetamine-type drugs with a wide polarity range have been screened in both human and horse urine using on-line pre-concentration on pre-columns packed with hydrophobic and cation-exchange sorbents in series and gradient microbore high-performance liquid chromatography. The underivatized amphetamines were identified by UV detection at 210 nm. The method has potential for the automated liquid chromatographic screening of amphetamines in urine, e.g., for doping control.
Vakkuri O, Salonen JS, Leppäluoto J, Anttila M, Karjalainen A, Järvensivu P.A sensitive and specific radioimmunoassay was developed for detomidine, 4(5)-(2,3-dimethylbenzyl)imidazole. The antibodies were raised in rabbits against a conjugate of detomidine and bovine thyroglobulin prepared by diazo reaction. Detomidine was iodinated with chloramine-T and immunoreactive tracer was purified in cation exchange chromatography. The sensitivity of the RIA was 1.6 fmol/tube allowing direct detomidine measurements from minute serum and urine samples (0.1-0.2 microliter) as well as tissue homogenates (10 microliters). For concentrations below 16 pmol/ml chloroform extraction wa...
Smith PB, Caldwell J, Smith RL, Horner MW, Moss MS.[phenyl-14C]-Phenylbutazone was administered to 2 horses p.o. and i.v. on separate occasions. Plasma levels and urinary and faecal elimination of 14C were monitored for up to 7 days after dosing. Phenylbutazone was rapidly and extensively absorbed after oral administration, and its bioavailability was 91% assessed by comparison of plasma AUCs of unchanged drug after p.o. and i.v. administration. The plasma elimination half-life of phenylbutazone was 9.7 h and this was independent of the route of administration. The pattern of elimination of phenylbutazone was independent of the route of admini...
Lees P, Taylor JB, Maitho TE, Millar JD, Higgins AJ.The pharmacokinetics, metabolism, excretion and tissue residues of phenylbutazone (PBZ) in the horse were studied following both intravenous and oral administration of the drug at a dose rate of 4.4 mg/kg. A 72-hour blood sampling schedule failed to demonstrate a third exponential phase; the plasma disposition following intravenous injection being described by a two compartment open model, with the following elimination phase parameters: beta = 0.13h-1, t1/2 beta = 5.46h, Vdarea = 0.141 1/kg and C1B = 17.9 ml/kg/h. The hydroxylated metabolites oxyphenbutazone (OPBZ) and gamma-hydroxyphenylbuta...
Sams R, Pizzo P.The possibility exists that ketamine, or ketamine in combination with xylazine, is being used illicitly to affect the performance of racehorses. This study was undertaken to identify the metabolites of ketamine in the urine of adult horses and to evaluate methods for detecting and confirming ketamine administration. Detection of ketamine and two ketamine metabolites is described using thin-layer chromatography (TLC) and their identities are confirmed by comparing their mass spectra and gas chromatographic retention times with those of authentic standards.
Nouws JF, Firth EC, Vree TB, Baakman M.Plasma disposition, protein binding, urinary recovery, and renal clearance of sulfamethazine (SMZ), sulfamerazine (SMR), and sulfadiazine (SDZ) and their N4-acetyl and hydroxy derivatives were studied in 4 horses in a crossover trial. The plasma concentration-time curves of the metabolites paralleled those of the parent drug in the elimination phase. Sulfamethazine and SMR were extensively metabolized. In plasma and urine, the main metabolite of the 3 sulfonamides tested was the 5-hydroxypyrimidine derivative, which was highly glucuronidated. Difference in elimination half-life of SMZ, SMR, an...
McKeever KH, Schurg WA, Jarrett SH, Convertino VA.The purpose of this study was to determine if a chronic hypervolemia would accompany endurance exercise training in the horse. Six mature previously inactive horses were utilized for this study. During the 5-wk experiment, five of the horses were trained for 14 d on a treadmill ergometer at a constant treadmill speed of 5.6 km X hr-1 and a constant grade of 12.5% for graduated lengths of time. One horse was trained by lunging at a trotting pace in a round pen. Following training, plasma volume increased by 4.7 1 (29.1%, P less than 0.05). Although the rate of daily water intake did not change ...
Ziemer EL, Parker HR, Carlson GP, Smith BP, Ishizaki G.An 11-year-old Quarter Horse mare and a 2-year-old Quarter Horse colt with clinical diagnoses of renal tubular acidosis (RTA) were donated to the University of California Veterinary Medical Teaching Hospital. A series of diagnostic tests was performed in an attempt to characterize the type and cause of RTA in these horses. Endogenous creatinine clearance and sodium sulfanilate clearance were within reference ranges; thus, no abnormality of glomerular function was detected. To assess renal tubular function in response to acid loading, each horse was given 0.1 g of NH4Cl/kg of body weight via na...
Houghton E, Dumasia MC, Teale P, Moss MS, Sinkins S.Esters of 19-nortestosterone form an important group of anabolic preparations used in veterinary practice. Based upon results from detailed metabolic studies for 19-nortestosterone in the horse, a method to confirm the administration of anabolic preparations of this steroid to castrated male horses and fillies is described; the method is based upon the use of multiple analytes. Following administration of the anabolic preparations, solid-phase extraction of urinary conjugates and the separation of the conjugate groups prior to hydrolysis allow for the determination of specific metabolites conj...
Dumasia MC, Houghton E, Moss MS, Chakraborty J, Marks V.The pro-drugs of dexamethasone, a potent glucocorticoid, are frequently used as anti-inflammatory steroids in equine veterinary practice. In the present study the biotransformation and urinary excretion of tritium labelled dexamethasone were investigated in cross-bred castrated male horses after therapeutic doses. Between 40-50% of the administered radioactivity was excreted in the urine within 24 h; a further 10% being excreted over the next 3 days. The urinary radioactivity was largely excreted in the unconjugated steroid fraction. In the first 24 h urine sample, 26-36% of the total dose was...
Glade MJ.In an attempt to validate the use of urinary creatinine concentration as an index of urinary flow rate, a series of timed quantitative urine collections were done on several groups of weanling and yearling ponies and Thoroughbreds. A total of 411 urine samples were generated by 19 ponies and 12 Thoroughbreds. Urinary flow rates and urinary creatinine concentrations were measured. When all the data were examined, urinary flow rates were independent of creatinine concentrations. However, for any given animal, daily urinary creatinine excretion was constant over several days, and urinary creatini...
Delbeke FT, Debackere M, Desmet N, Stevens M.Concentrations of the potent diuretic bumetanide were determined by a sensitive high performance liquid chromatographic procedure in plasma and urine from horses following intravenous and intramuscular administration of a dose rate of 15 micrograms/kg. The elimination half-life was found to be 6.3 min, the volume of distribution at steady state 68 ml/kg and the total plasma clearance 10.9 ml/min/kg. The onset of diuresis occurred within 15 min and diuresis was no longer apparent 1 h after i.v. administration. Given by the intramuscular (i.m.) route, bumetanide was rapidly absorbed; bioavailabi...
Blythe LL, Craig AM, Christensen JM, Appell LH, Slizeski ML.Dimethyl sulfoxide (DMSO) was administered IV to 6 Thoroughbred horses at 2 dosages: 1.0 g/kg and 0.1 g/kg. The pharmacokinetics seemed linear, with biological half-lives of 8.6 +/- 0.3 hours and 9.8 +/- 2.2 hours for the 1.0 g/kg and 0.1 g/kg dosages, respectively. This was further substantiated by mean residence times of 9.8 +/- 0.44 hours and 13.8 +/- 4.25 hours, areas under the curve of 12.55 +/- 1.42 mg/ml/hr and 1.63 +/- 0.49 mg/ml/hr, and the clearances of 0.081 +/- 0.009 L/kg/hr and 0.066 +/- 0.022 L/kg/hr for the large and small dosages, respectively. At 12 hours after 1.0 g/kg was ad...
Brown MP, Gronwall RR, Houston AE.Four healthy adult mares were each given a single injection of sodium cefoxitin (20 mg/kg of body weight, IV), and serum cefoxitin concentrations were measured serially during a 6-hour period. The mean elimination rate constant was 1.08/hour and the elimination half-life was 0.82 hour. The apparent volume of distribution (at steady state) and the clearance of the drug were estimated at 0.12 L/kg and 259 ml/hr/kg, respectively. Each mare and 2 additional mares were then given 4 consecutive IM injections of sodium cefoxitin (400 mg/ml) at a dosage of 20 mg/kg. Cefoxitin concentrations in serum, ...
Elfers RS, Bayly WM, Brobst DF, Reed SM, Liggitt HD, Hawker CD, Baylink DJ.The changes in serum and urinary levels of calcium and phosphorus and serum parathyroid hormone (PTH) were studied during controlled, chemically induced, acute renal disease in 4 ponies. There was an initial rise in daily urinary calcium and hydroxyproline excretion in 2 ponies which may have indicated increased bone resorption. Mild hypercalcemia, hypophosphatemia and elevated C-terminal PTH levels were associated with oliguria. Total daily urinary excretion of calcium and phosphorus decreased as oliguria developed. The levels of C-terminal PTH were increased in all four animals. This appears...
Bayly WM, Brobst DF, Elfers RS, Reed SM.Serum and urinary biochemical changes were recorded in 5 ponies in which acute tubular nephrosis had been induced over 5 days with mercuric chloride and potassium dichromate. Serum osmolality, the serum concentrations of urea nitrogen, creatinine, sodium, potassium and chloride, and blood pH and blood gases were measured daily for 14 days or until humane euthanasia was performed. Levels of the same substances were quantitated daily in urine. In addition, routine urinalyses and determination of urinary gamma glutamyl transferase (GGT) activity were performed on each sample. Changes in the value...
Kohn CW, Strasser SL.Urine samples were obtained from 6 healthy mares. During a 2-day acclimation period, mares were kept in stalls, fed sweet feed and mixed grass hay, and allowed free access to water and trace mineral salt. The mares were crosstied in their stalls within reach of hay, salt, and water for 24 hours during which urine was obtained by constant flow via indwelling Foley catheters. Twenty-four-hour urine production was 7,649 to 11,904 ml/day (mean = 9,212 +/- 1,9285) or 14.7 to 25.1 mlĝ/day. (mean = 19.3 +/- 4.1). Urinary excretion and clearance of electrolytes and protein were determined from aliquo...
Woods WE, Weckman T, Wood T, Chang SL, Blake JW, Tobin T.A commercially available radioimmunoassay kit was used to screen for the presence of etorphine in post-race urines from horses racing in Kentucky. Most horse urines contained small amounts of materials which reacted positively in this immunoassay. These materials are apparently endogenous to the horse and were called apparent etorphine equivalents. The levels of these apparent etorphine equivalents in post-race urines from 70 horses were estimated. Their modal level averaged 0.1 ng/ml, the population distribution was log normal, and individual horses showed levels of up to 0.8 ng/ml.
Snyder JR, Pascoe JR, Hietala SK, Holland M, Baggot DJ.Gentamicin sulfate (2.2 mg/kg of body weight, IV) was given to anesthetized horses. Jejunal and large colon tissue samples (1 g), serum, and urine were collected over a 4-hour period. Maximum gentamicin concentrations in serum (10.06 +/- 2.85 micrograms/ml) occurred at 0.25 hours after injection. Maximum gentamicin concentrations in the large colon (4.13 +/- 1.80 micrograms/ml) and jejunum (2.26 +/- 1.35 micrograms/ml) occurred in horses at 0.5 and 0.33 hours, respectively. Tissue concentrations decreased in parallel with serum concentrations and were still detectable at the end of the 4-hour ...
Dumasia MC, Houghton E, Sinkins S.A gas chromatographic-mass spectrometric (GC-MS) method using three analytes to detect and confirm the administration to equine male castrates of veterinary pro-drugs based upon esters of testosterone is described. The method involves extraction of steroid conjugates from horse urine by C18-bonded cartridges and fractionation into glucuronic acid and sulpho-conjugates by Sephadex LH-20 column chromatography. After deconjugation, the free neutral steroids were partially purified by thin-layer chromatography and following derivatization (methyloxime-trimethylsilyl ether) were analysed by capilla...
Robb EJ, Kronfeld DS.A 3-year-old mare repeatedly had clinical signs of rhabdomyolysis on mild exertion. Serum creatine kinase and aspartate transaminase activities were high at rest. Responses to dietary sodium bicarbonate were tested through 7 alternating periods of supplementation of a basal ration of timothy hay and oats. Physical signs; venous blood pH and gases; blood glucose and lactate; serum electrolytes, enzymes, and creatinine; and urine pH were monitored before and after exercise. Dietary sodium bicarbonate raised resting venous blood pH and bicarbonate slightly and significantly increased urine pH fro...
Trim CM, Hanson RR.The intravenous administration of xylazine (1.1 mg/kg bodyweight) in six ponies resulted in a significant increase in urine output over two hours, with maximum flow occurring between 30 and 60 minutes after injection. Urine specific gravity, osmolality and glucose concentration decreased. Renal clearance of endogenous creatinine was unchanged. Significant increases in the excretion of potassium and chloride occurred. Plasma glucose concentration was increased 30 minutes after the administration of xylazine by a mean value of 37 per cent. Serum osmolality and sodium, potassium and chloride conc...
Johansson IM, Anlér EL, Bondesson U, Schubert B.Two metabolites of meclofenamic acid have been isolated from equine urine. Both metabolites are found to be monohydroxylated forms of meclofenamic acid by gas chromatography-mass spectrometry after extractive alkylation. The parent drug and the metabolites are separated by reversed-phase liquid chromatography on a Spherisorb ODS column, using methanol-phosphate buffer eluents and UV detection at 280 nm. The structure of the metabolites is discussed on the basis of LC, TLC and GC-MS data.
Skrabalak DS, Henion JD.Betamethasone and its major unconjugated metabolite, 6-beta-hydroxybetamethasone, were detected in equine urine by thin-layer chromatography and characterized by micro-liquid chromatography/mass spectrometry (micro-LC/MS). Their structures were confirmed by a combination of infrared spectroscopy and nuclear magnetic resonance spectroscopy.
Her GR, Watson JT.Sensitive and specific methodology based on capillary column gas chromatography-electron capture-negative chemical ionization-mass spectrometry has been developed for the quantitative analysis of corticosteroids from biological fluids. The feasibility of this method is demonstrated in the quantitative analysis of dexamethasone in horse urine following administration of the drug. A structurally similar compound, 6 alpha-methylprednisolone, is added to the urine as an internal standard. The free dexamethasone and the internal standard are extracted and oxidized to high-electron-affinity 1,4-andr...
Mutoh K, Watanabe S, Wakuri H.The glands of pelvis renalis in adult and fetal horses were examined by histochemically. The glandular terminal was divided into two types, intraepithelial gland (IE) and extraepithelial gland (EE) by their locations and histochemical characters. Both glands were composed of mucous cells. The former lay in the transitional epithelium and were stained reddish with galactose oxidase-Schiff (GOS) and mild oxidation-Schiff (MOS), bluish purple with periodic acid-cold thionine Schiff-NaOH-PAS (PCP). The latter distributed in the lamina propria, but was not discovered in the fetus. They were stained...
Cartoni GP, Montanaro M.The results and the improvement of the analytical procedures adopted for the control of doping in horses will be reported. This control has been systematically carried out in Italy for about 10 years in the laboratories of Italian Federation of Sport and Medicine in which the biological samples for the control of doping in various sport activities (football, cycling, athletics etc.) are also examined. In this way it is possible to use the same instruments for all these similar problems and compare the results. The analytical procedure is based on the following steps: 1) Extraction of the sampl...
Chou CC, Chen CL, Asbury AC, Webb AI, Vickroy TW.To develop an ELISA that is sensitive and suitable for measurement of immunoreactive acepromazine (ACP) in horse serum and urine and to determine the acute effects of exercise on immunoreactive ACP values in Thoroughbreds. Methods: 12 healthy Thoroughbreds (5 mares, 5 geldings, 2 stallions), aged 2 to 8 years. Methods: A commercially available antibody and a horseradish peroxidase-conjugated oxime derivative of immunoreactive ACP were used to develop a one-step ELISA. Horses were used in a crossover design study to evaluate possible effects of treadmill exercise on serum and urine ACP concentr...
Van Eenoo P, Delbeke FT, Roels K, Baert K.Non-steroidal anti-inflammatory drugs (NSAIDs) are prohibited by the International Federation of Horse Racing Authorities but are commonly used in veterinary practice. Plasma and urinary concentrations of the NSAID tolmetin were determined by a high-performance liquid chromatographic procedure with UV detection following oral administration of a dose of 1 g to six fasted untrained standard bred mares. With a limit of quantitation (LOQ) of 0.05 microg/ml tolmetin was present in plasma for 9-12 h post-administration. Maximum concentrations of 2.1+/-0.89 microg/ml were found after 0.7+/-0.25 h. T...
Roberts CJ, Jackson LS.The development, validation, and application of an ELISA for dexamethasone in equine urine is described. The drug-protein conjugate was immobilised in microtitre plate wells and antiserum raised against the same drug-protein conjugate was allowed to compete with sample or standard drug and the immobilised drug-protein conjugate. The proportion of antiserum binding to the immobilised drug-protein conjugate was detected using a biotinylated protein G/extravidin-alkaline phosphatase complex in situ and measurement of the substrate product. The method was used to detect the presence of drug-derive...
Black SB, Stenhouse AM, Hansson RC.This paper details various rapid and sensitive methods for the extraction and derivatisation of propranolol, metoprolol, sotalol, atenolol, pindolol, timolol, oxprenolol, alprenolol and penbutolol in equine urine and in human post mortem whole blood and urine. Three solid-phase extraction methods are described involving the use of either XtrackT XRDAH515, Bond Elut Certify or Sep-Pak C18 cartridges. Two derivatisation methods are also described involving the formation of cyclised silyl or pentafluoropropionate derivatives with either chloromethyldimethylchlorosilane or pentafluoropropionic anh...
Kim Y, Seo C, Oh S, Kwak J, Jung S, Sin E, Kim H, Ji M, Lee HS, Park HJ, Lee G, Yu J, Kim M, Lee W, Paik MJ.Loxoprofen is a non-steroidal anti-inflammatory drug of the 2-arylpropionic acid type, which has used to treat musculoskeletal disorders in the horse racing industry. However, it has also used illicitly to mask clinical signs of inflammation and pain in racehorses. Thus, its accurate analysis has become an important issue in horse doping laboratories. In this study, an analytical method of loxoprofen was developed as tert-butyldimethylsilyl (TBDMS) derivative by gas chromatography-mass spectrometry (GC-MS). Characteristic fragment ions of [M-15], [M-57], and [M-139] permitted the accurate and ...
Delbeke FT, Landuyt J, Debackere M.A high-performance liquid chromatographic method to measure plasma and urinary alclofenac levels in equine biofluids is described. Isolation of the drug from plasma is achieved using liquid-liquid extraction with diethyl ether. Reversed-phase C18 solid phase extraction is used for the extraction of free and conjugated alclofenac from urine. The reproducibility and accuracy of the method were well within acceptable limits over the concentration ranges 0-10 and 0-20 micrograms/ml, respectively, for plasma and urine. Starting with 2 ml of plasma, a concentration of 0.1 microgram/ml could easily b...
Hülsemann F, Flenker U, Machnik M, Schänzer W.Sodium bicarbonate administration to horses prior to competition in order to enhance the buffer capacity of the organism is considered as a doping offence. The analysis of the isotopic composition of urinary bicarbonate/CO(2) (TCO(2)) may help to identify an exogenous bicarbonate source, as technical sodium bicarbonate exhibits elevated delta(13)C values compared with urinary total carbon. The isolation of TCO(2) from 60 equine urine samples as BaCO(3) followed by an isotopic analysis shows a significant variability of delta(13)C for TCO(2) of more than 10 per thousand. The delta(13)C of total...
Bland SA, Blake JW, Ray RS.Mefenamic acid is extracted from biological fluids and is acylated with pentafluoropropionic anhydride to form a derivative possessing high electron affinity. The derivative is analyzed by gas-liquid chromatography with an electron capture detector. The method is particularly valuable for determining drug levels in blood where small sample and/or drug concentrations are available.
Ketelaars HC, Peters JG, Anzion RB, Van Ginneken CA.The isolation, partial identification and quantitative determination of four guaiphenesin glucuronides in plasma and urine of the horse is described. The identity of the glucuronides was checked by UV and fluorescence spectrophotometry, by NMR spectrometry and by mass spectrometry after permethylation. The applicability of the procedure to pharmacokinetic studies is demonstrated.
Leung DKK, Wong ASY, Zhou QL, Wan TSM, Ho ENM.A non-target variable Data Independent Acquisition (vDIA) workflow based on accurate mass measurements using a Q Exactive OrbiTrap is presented for the first time for equine doping control testing. The vDIA workflow uses a combination of MS1 events (1 to 2) and multiple vDIA events to cover the analytes of interest. The workflow basically captures a digital image of a sample allowing all relevant MS1 and MS2 data to be recorded. In theory, the workflow can accommodate an unlimited number of analytes as long as they are amenable to the sample extraction protocol and fall within the mass limits ...
Divers TJ, Byars TD, Murch O, Sigel CW.Proteus mirabilis cystitis was induced in 9 ponies by chemically eroding the bladder mucosa before the organism was inoculated. Comparisons were made in the treatment of P mirabilis cystitis between ponies treated daily for 13 days with a trimethoprim-sulfadiazine (TMP-SDZ) paste and both positive and negative controls. Urine cultures from ponies treated with TMP-SDZ became negative for P mirabilis between days 3 and 9 after the start of the treatment, whereas positive controls remained infected until day 13. Urine cultures from all ponies were negative for P mirabilis on day 28. Urine concent...
Skrabalak DS, Cuddy KK, Henion JD.Micro-liquid chromatography-mass spectrometry (micro-LC-MS) was utilized to quantitatively determine betamethasone and its major unconjugated metabolite, 6 beta-hydroxybetamethasone, in equine plasma and urine. The advantage of micro-LC-MS over conventional gas chromatography-mass spectrometry in corticosteroid determination is illustrated and the reliable, steadfast nature of micro-LC-MS is demonstrated through example.
Törneke K, Larsson CI, Appelgren LE.Isoxsuprine is used in veterinary medicine as a vasodilating agent. The drug has been detected in the urine of horses up to 6 weeks after the cessation of administration. In the present study, the distribution pattern of 3H-isoxsuprine was investigated using whole body autoradiography in mice to find a possible site of retention. Melanin was the only place of retention identified. Additional in vitro studies showed an affinity of isoxsuprine to both melanin and keratin. The K(d) values were 0.02 mmol/l and 1 mmol/l, and the B(max) values were 0.2 micromol/mg and 2 micromol/mg, respectively. A ...
Uboh CE, Soma LR, Rudy JA, Morgan E, Mengeringhausen K, Sams R.This study was undertaken to determine the applicability of plasma concentration of furosemide and specific gravity (SG) of urine in regulating the use of furosemide administered 4 hours prior to race time in Exercise-Induced Pulmonary Hemorrhage (EIPH) race horses. Nonbleeders (CTL) and certified bleeders (FUR) actively racing in Illinois (IL) and Pennsylvania (PA) were used in the study. Various doses (less than 250, 250, 300, 350, 400 and 500 mg) were administered either as a single intravenous (IV) dose or as a combination (IV-IM) of IV and intramuscular (IM) administrations 4 hours before...
Hunt JP, Haywood PE, Moss MS.A gas chromatographic screening procedure for the non-steroidal anti-inflammatory group of drugs is described. The method invovles on-column methylation of the carboxylic acid group using trimethylanilinium hydroxide as the methylating reagent. Fifteen such drugs were studied. Eight of these were detected in urine collected from horses that had received these compounds orally and for these drugs, rates of urinary excretion are recorded. Seven other members of this group of drugs were shown to be detectable by this procedure but in these cases the drug was added to urine and not administered to...
Singh AK, Mishra U, Ashraf M, Abdennebi EH, Granley K, Dombrovskis D, Hewetson D, Stowe CM.Chemical ionization- and electron impact ionization-selective ion monitoring provided a simple and sensitive method for measuring detomidine (Domosedan), a potent sedative-analgesic drug for horses and cattle. Chemical ionization was at least 10 times more sensitive than electron impact ionization. By using propranolol as an internal standard, we found that the recovery of detomidine from the extraction procedure used in this study was greater than 75% for plasma, whole blood, or urine samples. Approximately 68% of detomidine was bound to plasma protein and 53% was bound to red blood cells.
Lehner AF, Almeida P, Jacobs J, Harkins JD, Karpiesiuk W, Woods WE, Dirikolu L, Bosken JM, Carter WG, Boyles J, Holtz C, Heller T, Nattrass C....Remifentanil (4-methoxycarbonyl-4-[(1-oxopropyl)phenylamino]-1-piperidinepropionic acid methyl ester) is a mu-opioid receptor agonist with considerable abuse potential in racing horses. The identification of its major equine urinary metabolite, 4-methoxycarbonyl-4-[(1-oxopropyl)phenylamino]-1-piperidinepropionic+ ++ acid, an ester hydrolysis product of remifentanil is reported. Administration of remifentanil HCl (5 mg, intravenous) produced clear-cut locomotor responses, establishing the clinical efficacy of this dose. ELISA analysis of postadministration urine samples readily detected fentany...
Soma LR, Uboh CE, Guan F, Moate P, Luo Y, Teleis D, Li R, Birks EK, Rudy JA, Tsang DS.The pharmacokinetics of clenbuterol (CLB) following a single intravenous (i.v.) and oral (p.o.) administration twice daily for 7 days were investigated in thoroughbred horses. The plasma concentrations of CLB following i.v. administration declined mono-exponentially with a median elimination half-life (t(1/2k)) of 9.2 h, area under the time-concentration curve (AUC) of 12.4 ng.h/mL, and a zero-time concentration of 1.04 ng/mL. Volume of distribution (V(d)) was 1616.0 mL/kg and plasma clearance (Cl) was 120.0 mL/h/kg. The terminal portion of the plasma curve following multiple p.o. administrati...
Edlund PO, Bowers L, Henion J.Monitoring steroid use requires an understanding of the metabolism in the species in question and development of sensitive methods for screening of the steroid or its metabolites in urine. Qualitative information for confirmation of methandrostenolone and identification of its metabolites was primarily obtained by coupled-column high-performance liquid chromatography-tandem mass spectrometry. The steroids and a sulphuric acid conjugate were isolated and identified by their daughter ion mass spectra in the urine of both man and the horse following administration of methandrostenolone. Spontaneo...
Levina V, Timms M, Vine J, Steel R.A synthetic Interleukin-1 receptor antagonist peptide with the sequence Acetyl-Phe-Glu-Trp-Thr-Pro-Gly-Tyr-Trp-Gln-Pro-Tyr-Ala-Leu-Pro-Leu-OH has been identified in a vial seized during a stable inspection. The use of peptide-based Interleukin-1 receptor antagonists as anti-inflammatory agents has not been previously reported, making this peptide the first in a new class of sports doping peptides. The peptide has been characterized by high-resolution mass spectrometry and a detection method developed based on solid-phase extraction and liquid chromatography - triple quadrupole mass spectrometr...
Soraci AL, Mestorino ON, Errecalde JO.The pharmacokinetics and bioavailability of cefoperazone (CPZ) were studied following intravenous (IV) and intramuscular (IM) administration of single doses (30 mg/kg) to horses. Concentrations in serum, urine and synovial fluid samples were measured following IV administration. CPZ concentrations in serum, synovial fluid and spongy bone samples were measured following IM administration. After IV administration a rapid distribution phase (t1/2 (alpha): 4.22 +/- 2.73 min) was followed by a slower elimination phase (t1/2(beta) 0.77 +/- 0.19 h). The apparent volume of distribution was 0.68 +/- 0....
Combie J, Blake JW, Nugent TE, Tobin T.We have investigated the action of five sources of beta-glucuronidase enzymes on the hydrolysis of glucuronides of apomorphine, butorphanol, hydromorphone, nalbuphine, oxymorphone and pentazocine in equine urine. For all glucuronides tested, Patella vulgata beta-glucuronidase yielded the largest thin layer chromatographic (TLC) spots. For oxymorphone, P. vulgata was the only treatment to yield detectable TLC spots under test parameters. For these six drugs, TLC spot size and chromatographic quality were compared between control horses and horses pretreated with furosemide four hours earlier. F...
Morgan RA, Malalana F, McGowan CM.A 14-year-old Cleveland Bay cross gelding was presented with severe urinary incontinence that had been present for 1 year, and chronic polydipsia and polyuria over 4 years. Water intake had been recorded as 240 L over a 24-hour period. Results: The horse had marked urinary incontinence and polyuria and polydipsia. The urine was markedly hyposthenuric, but no abnormalities on urinalysis were detected. There were no other abnormal clinical or neurological signs. Haematological and serum biochemical examinations showed no abnormalities and ultrasonographic and endoscopic examination of the urinar...
Houghton E, Copsey J, Dumasia MC, Haywood PE, Moss MS, Teale P.As part of a continuing research program associated with the detection of anabolic steroid residues in horse urine, normal samples from entire male horses have now been investigated. Isomers of three C-18 neutral steroids; 4-estren-17-ol-3-one (1), estrane-3,17-diol (2) and an unsaturated estranediol having a possible structure (3), have been identified in urine samples from two male horses aged 8 and 14 years. Of these three steroids, compound (2) was not detected in the urine of a 2.5 yr old entire male nor in the majority of post-race urine samples from entire male horses average age 3.8 yr...
Marland A, Sarkar P, Leavitt R.Tenoxicam (Mobiflex) was administered orally to four standardbred mares at a dose of 200 mg. Elimination profiles of tenoxicam and hydroxytenoxicam were generated based on quantitation of these analytes in urine and serum by liquid chromatography (LC) with ultraviolet detection. Tenoxicam was confirmed by LC-tandem mass spectrometry daughter ion mass spectra in the last postadministration sample in which tenoxicam was detected. The tenoxicam and hydroxytenoxicam urinary elimination profiles had the same shape for the same horse; however, each horse was significantly different from the others. ...
Brotherton HO, Yost RA.A screening and confirmation procedure for drugs and metabolites in the blood serum and urine of racing animals was developed. Equine blood serum was spiked with low concentrations of several drugs of interest. Canine blood serum and urine were collected following oral doses of diethylcarbamazine, procaine, and phenylbutazone. Serum, urine, and extracts of each were analyzed, using a triple quadrupole mass spectrometer. Simultaneous screening of up to 50 drugs was possible in a single sample, in less than 2 minutes. Detection limits for most compounds were in the ng/ml to microgram/ml range, u...
Vonaparti A, Lyris E, Panderi I, Koupparis M, Georgakopoulos C.Two simple and rapid LC/MS methods with direct injection analysis were developed and validated for the quantification and identification of hydrocortisone in equine urine using the same sample preparation but different mass spectrometric systems: ion trap mass spectrometry (IT-MS) and time-of-flight mass spectrometry (TOF-MS). The main advantage of the proposed methodology is the minimal sample preparation procedure, as particle-free diluted urine samples were directly injected into both LC/MS systems. Desonide was used as internal standard (IS). The linear range was 0.25-2.5 microg ml(-1) for...
Camargo FC, Robinson NE, Dirikolu L, Berney C, Eberhart S, Derksen FJ, Lehner AF, May J, Hughes C, Tobin T.Trimetoquinol (TMQ) is a very potent and fast acting bronchodilator in horses with heaves. This study assessed the plasma and urinary concentrations of TMQ in horses with heaves following administration via the intravenous (IV, 0.2 microg/kg) and intra-tracheal (IT, 2 microg/kg) routes. TMQ was administered to six horses affected with heaves (RAO - Recurrent Airway Obstruction, used interchangeably) by the above routes and plasma and urine samples collected and stored at -20 degrees C until analyzed. Solid Phase Extraction (SPE) of TMQ was followed by highly sensitive ESI(+)-LC-MS-MS (ElectroS...
