(a) The purpose of this chapter is to protect the integrity of horse and greyhound racing, to ensure the health of race animals, and to safeguard the interests of the public and the participants in racing through the prohibition and control of all prohibited drugs, chemicals, and other substances.(b) For purposes of this chapter, "prohibited drugs, chemicals, or other substances" means:(1) any stimulants, depressants, tranquilizers, local anesthetics, drugs, other drug metabolites which could affect the health or performance of a race animal, however minimal, except as expressly permitted by this chapter;(2) a drug permitted by this chapter in excess of the maximum or other restrictions in this chapter;(3) a substance present in the race animal in excess of a concentration at which such a substance could occur naturally; and(4) a drug or substance, regardless of how harmless or innocuous it might be, which interferes with the detection of stimulants, depressants, tranquilizers, local anesthetics, drugs, or drug metabolites which could affect the health or performance of a race animal, however minimal, or quantitation of drugs permitted by this chapter.