Researchers Validate New Equine Drug-Testing Method

Researchers Validate New Equine Drug-Testing Method

Photo: Anne M. Eberhardt/The Horse

With so many doping agents out there and new substances constantly coming into play, it can be challenging for laboratories to keep up with doping control. When timing and pricing come into play, it can be even more difficult. But researchers in Hong Kong have recently validated a new, easy, “dilute-and-shoot” method that can check for more than 40 of the most difficult-to-detect drugs simultaneously. The test is quick, easy, effective, and cost-efficient.

“By employing high-resolution mass spectrometry in the full-scan mode, we can detect, theoretically, an unlimited number of targeted drugs in a single run, provided that all these drug targets can be ionized and detected in the instrument,” said Terence S.M. Wan, PhD, EurChem, CSci, CChem, FRSC, FAORC, FCSFS, head of the racing laboratory and chief racing chemist at The Hong Kong Jockey Club. “That means new drug targets can easily be incorporated into these methods as well.”

The “dilute-and-shoot” method already exists in human doping control, but it hasn’t been adopted as a widespread method in equine testing, Wan said. Many current methods in equine testing require an intermediate step of substance extraction from the sample. This step is not only time-consuming, but it’s also “quite ineffective” for very polar (waterlike) or zwitterionic (neutral molecules having both positive and negative charges) substances because it’s hard to extract them from water-based biological fluids.

With “dilute-and-shoot,” however, there’s just a simple dilution step before injecting the sample directly into the analytical instrument. “This requires minimal effort in sample preparation, which makes it quick and easy,” Wan said.

In their research, Wan and his colleagues investigated the “dilute-and-shoot” method to check for the presence of 46 polar drugs in both plasma and urine from horses. Tested drugs included angiotensin-converting enzyme inhibitors, sympathomimetics, anti-epileptics, hemostatics, and a new doping agent called 5-aminoimidazole-4-carboxamide-1-beta-D-ribofuranoside (or AICAR), Wan said. They also tested for two threshold or residue-limit substances—dimethyl sulfoxide (better known as DMSO) and theobromine—which are regulated by signatory countries of the International Federation of Horseracing Authorities.

“We are pleased that these plasma and urine methods have proven to be reliable for qualitative identification purposes,” he said.

Even so, Wan cautioned that a single testing method is clearly insufficient. “One should appreciate that, in order to secure the widest possible drug coverage, doping control testing of horse blood and urine samples would actually utilize not one but numerous different and complementary test methods,” he said.

Such doping control progress is only possible with the support of the racing and equestrian competition industries, Wan added. “Regulatory authorities and international federations should continue to provide adequate resources to support doping control laboratories to enhance their testing capability,” he said.

“With the rapid development of new drugs, and in order to sustain testing capability into the future, continual development of new test methods by doping control laboratories is essential. Good testing capability not only leads to effective doping control—thereby ensuring a level playing field and protecting all those abiding by the rules of competition—but can also be an effective deterrent against doping.”

The study, “Doping control analysis of 46 polar drugs in horse plasma and urine using a 'dilute-and-shoot' ultra high performance liquid chromatography-high resolution mass spectrometry approach,” was published in the Journal of Chromatography A

About the Author

Christa Lesté-Lasserre, MA

Christa Lesté-Lasserre is a freelance writer based in France. A native of Dallas, Texas, Lesté-Lasserre grew up riding Quarter Horses, Appaloosas, and Shetland Ponies. She holds a master’s degree in English, specializing in creative writing, from the University of Mississippi in Oxford and earned a bachelor's in journalism and creative writing with a minor in sciences from Baylor University in Waco, Texas. She currently keeps her two Trakehners at home near Paris. Follow Lesté-Lasserre on Twitter @christalestelas.

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