Determination of methylxanthine stimulants in urine of racing greyhounds by high-performance liquid chromatography. Resolution of a contested drug administration case.

Results of urine drug analyses for three racing greyhounds that tested positive for caffeine in this laboratory were contested by the animal trainer, who asserted that positives were achieved from deliberate chocolate feeding by a rival kennel. The metabolism and excretion of methylxanthines was examined by high-performance liquid chromatography of extracts of the urine of racing greyhounds force-fed either caffeine (No Doz) or chocolate (Hersheys chocolate drops). Samples from untreated animals served as controls. Study results showed that test animals fed chocolate could be very easily distinguished from those fed caffeine. While the former animals exhibited a prominent theobromine peak with trace amounts of caffeine and theophylline, the caffeine-treated animals gave a prominent caffeine peak with moderate theophylline levels and almost nondetectable theobromine amounts. When these results were compared with the results from the positive authentic racing animals, chocolate feeding was clearly ruled out as an alternative to caffeine administration.