Large or Food Animal and Equine Medicine Commons^™

The Detection, Pharmacokinetics And Behavioral Effects Of Diisopropylamine Dichloroacetate (Dada) In The Horse: A Preliminary Report, J.-M. Yang, W. E. Woods, T. J. Weckman, T. W. Wood, S.-L. Chang, J. W. Blake, Thomas Tobin

Maxwell H. Gluck Equine Research Center Faculty Publications

1. Drug administration studies using diisopropylamine dichloroacetate (DADA) and diisopropylamine (DIPA) were conducted in Thoroughbred and Standardbred horses to assess physiological effects and develop detection methods.

2. Four horses received 0.08 mg DADA/kg body wt and showed no changes in heart and respiratory rates or body temperature as measured over a 1-hr period after administration. A transient diuretic effect was found to occur in 2 mares dosed with 0.80 mg DADA/kg body wt.

3. A qualitative detection method using thin-layer chromatography was developed to detect DIPA, the major metabolite of DADA in equine urine. A quantitative detection method (lower limit …

Phenylbutazone In The Horse: A Review, Thomas Tobin, S. Chay, S. Kamerling, W. E. Woods, T. J. Weckman, J. W. Blake, P. Lees

Maxwell H. Gluck Equine Research Center Faculty Publications

Phenylbutazone is an acidic, lipophilic, nonsteroidal anti-inflammatory drug (NSAID). It is extensively metabolized in the horse. The metabolites so far identified, oxyphenbutazone, y-hydroxyphenylbutazone and y-hydroxyoxyphenbutazone. account for some 25-30% of administered dose over 24 h. The plasma half-life of phenylbutazone and termination of its pharmacological action are determined primarily by its rate of hepatic metabolism. Phenylbutazone acts by inhibiting the cyclooxygenase enzyme system, which is responsible for synthesis of prostanoids such as PGE?. It appears to act on prostaglalidin-H synthase and prostacyclin synthase, after conversion by prostaglandin-H synthase to reactive intermediates. It markedly reduces prostanoid-dependent swelling, edema, erythema, and hypersensitivity …

Pharmacokinetics And Protein Binding Of Morphine In Horses, Joan Combie, Thomas E. Nugent, Thomas Tobin

Maxwell H. Gluck Equine Research Center Faculty Publications

Morphine could be detected in horses dosed with 0.1 mg of drug/kg of body weight for up to 48 hours in blood and 144 hours in urine. This dose of morphine elicited no observ­able effects and is a suggested an­algesic dose. Computer analysis revealed that a 3-compartment open system was the best fitting model with a serum half life of 87.9 minutes and a urine half life of 101.1 minutes. Binding to equine serum proteins was linear over a drug con­centration range of 3.88 x 10-5M to 3.50 x 10-aM and averaged 31.6%. In RBC-partitioning experiments, 78.1 % of the …

A Review Of The Pharmacology, Pharmacokinetics And Behavioral Effects Of Procaine In Thoroughbred Horses, Thomas Tobin, J. W. Blake

Maxwell H. Gluck Equine Research Center Faculty Publications

Since procaine has both local anaesthetic and central stimulant actions its presence in the blood or urine of racing horses is forbidden. After rapid intravenous injection of procaine HC1 (2.5 mg/Kg) in thoroughbred mares plasma levels of this drug fell rapidly (t 1/2 alpha = 5 min) and then more slowly (t 1/2 beta = 50.2 min). These kinetics were well fitted by a two compartment open model (Model I). This model gave an apparent Vdbeta for procaine in the horse of about 3,500 litres. Since procaine was about 45% bound to equine plasma protein this gives a true Vdbeta …

The Gas-Liquid Chromatograph And The Electron Capture Detection In Equine Drug Testing., J. W. Blake, Thomas Tobin

Maxwell H. Gluck Equine Research Center Faculty Publications

Three gas-liquid chromatographic (G.L.C.) procedures discussed have been designed around the four "esses" of detection tests--speed, sensitivity, simplicity, and specificity. These techniques are admirably applicable to the very low plasma drug levels encountered in blood testing under pre-race conditions. The methods are equally applicable to post-race testing procedures, where both blood and urine samples are tested. Drugs can only rarely be detected by the electron capture detector (E.C.D.) without a prior derivatization step, which conveys to the drug(s) high electron affinity. Because of broad applicability, two derivatizing agents, heptafluorobutyric (HFBA) and pentafluorpropionic (PFPA) anhydrides are employed. The three techniques, allowing …