Large or Food Animal and Equine Medicine Commons^™

Frequency Distribution Of Post Race Urine Ph From Standardbreds Compared With Thoroughbreds: Research And Regulatory Significance, S. D. Stanley, R. A. Sams, J Daniel Harkins, G. D. Mundy, J. Boyles, W. E. Woods, Thomas Tobin

Maxwell H. Gluck Equine Research Center Faculty Publications

The concentration of drugs and drug metabolites in urine samples of racing horses is strongly influenced by urine pH(Tobin, 1981), depending on whether the drugs are weak acids or weak bases. Drugs that are weak acids tend to concentrate in besic urine. In contrast, drugs that are weak bases tend to concentrate in acidic urine. These relationships have a well-established theoretical basis (the Henderson-Hasselbalch relationship) and have been demonstrated repeatedly in experimental animals and man (Tobin, 1981). More recently, evidence suggests that these relationships also occur with clinically and forensically significant agents in equine urine (Wood, et al. 1990; Gerken …