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Clenbuterol plasma pharmacokinetics in cattle
M Dave1, M J Sauer, R J Fallon
1Risk Research Department, Veterinary Laboratories Agency, Addlestone, Surrey, UK.
The Analyst
|August 6, 1999
Summary
Plasma clenbuterol (Cb) concentrations can distinguish between therapeutic use and illicit growth promotion in cattle. A plasma Cb level over 1.63 ng/mL indicates growth-promoting dosages, aiding regulatory control.
Area of Science:
- Veterinary Pharmacology
- Animal Science
- Food Safety
Background:
- Clenbuterol (Cb) is used therapeutically but also illicitly as a growth promoter in cattle.
- Distinguishing between these uses via plasma concentration analysis is crucial for regulatory oversight.
Purpose of the Study:
- To investigate clenbuterol pharmacokinetics in cattle.
- To determine if plasma clenbuterol concentrations can differentiate therapeutic from growth-promoting administration.
Main Methods:
- Cattle received either therapeutic (0.8 µg/kg twice daily) or growth-promoting (10 µg/kg twice daily) clenbuterol doses.
- Plasma clenbuterol concentrations were measured using direct enzyme immunoassay.
- A two-compartment model was used to analyze pharmacokinetic data.
Main Results:
- Steady-state plasma pharmacokinetics were achieved after 3 days (therapeutic) and 5 days (growth-promoting).
- Tolerance limit analysis showed plasma clenbuterol concentrations >1.63 ng/mL (p < 0.01) indicated growth-promoting doses.
Conclusions:
- Plasma clenbuterol analysis is a viable method to differentiate therapeutic use from illicit growth promotion in cattle.
- Establishing a threshold concentration aids in detecting illegal use and ensuring animal product safety.
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