RESIDUES OF THE BETA-AGONIST CLENBUTEROL IN TISSUES OF MEDICATED FARM-ANIMALS

Reports of the illegal use of clenbuterol as a growth promotant prompt ed the development of a competitive enzyme immunoassay for this drug. This procedure was utilized to study the elimination of clenbuterol fr om tissues in sheep medicated with both therapeutic and growth-promoti ng doses of the drug. The results indicated that prior to removal of m edication clenbuterol was widely distributed throughout the animal tis sues. However as the withdrawal periods increased fluid targets such a s urine and bile became less effective at detecting clenbuterol usage. At both therapeutic and growth-enhancing concentrations of clenbutero l liver samples remained positive up to the maximum withdrawal time gi ven in this experiment (15 days). Concentrations of clenbuterol likely to cause food poisoning (> 100 ng/g) were only detected in liver samp les taken prior to the removal of medication. The highest recorded con centration of clenbuterol in muscle was 22.5 ng/g.