J. W. Blake

Testing for drugs in horses

Summary Drug testing today depends primarily on post-race urine testing, with blood testing and pre-race testing as adjuncts to the testing process. Drugs are extracted from urine by a process called liquid-liquid extraction, and then screened for the presence of illegal agents. Screening is generally done by Thin Layer Chromatography (TLC analysis). If a drug is detected in the screening process, its presence in the sample is confirmed by other chromatographic methods, and most especially by Gas Chromatography-mass Spectrometry (GC-MS.) The qualitative detection of drugs in forensic samples is a well worked-out art, and most drugs can be identified in blood or urine samples with a high degree of accuracy. Drugs can be quantitated in blood or urine with an accuracy of plus or minus 25% or more. Thesescientific determinations on a sample can be independently verified in referee samples, and form the scientific basis of the regulatory process of medication control.

The detection, pharmacokinetics and behavioral effects of diisopropylamine dichloroacetate (DADA) in the horse: A preliminary report

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 of detection 0.5 micrograms/ml urine) for this metabolite was also developed using gas chromatography. 4. Neither DADA or the free base, DIPA, were detectable in equine blood samples using the above-mentioned methodologies.

Pre-purchase testing for drugs in horses: A review

Summary The use of medications to mask defects of wind, limb or temperament in horses offered for sale can be a problem for purchasers, and for veterinarians performing pre-purchase examinations. Drugs which may be used in this way include the phenylbutazone-like drugs, cotricosteroids, local anaesthetics, and tranquilizers. If skillfully used, no signssuggestive of medication by these agents will be detectable by the examining veterinarian. In the absence of information on the medications status of an animal, the usefulness of a pre-purchase examination may be limited. These limitations can be circumvented by the analysis of blood or more expecially blood and urine samples from such horses. Current analytical methodology allows the detection of many medications in blood, and of virtually all significant medications if blood and urine samples are available. Such analysis, therefore, allows the veterinary practitioner to offer a significantly better pre-purchase test, and protects both the veterinarian and the purchaser.