Distribution of blood-muscle for clenbuterol in rat using microdialysis.
Clenbuterol is clinically used as a bronchodilator, but it is also illegally used to increase lean meat in animal husbandry. To investigate the muscle distribution of protein-unbound clenbuterol, a microdialysis technique coupled to liquid chromatography system was applied to simultaneously monitor clenbuterol in rat blood and muscle. Two microdialysis probes were implanted into the jugular vein/right atrium and hind leg muscle of rat for sampling after clenbuterol administration (10 mg/kg) through the femoral vein. Dialysate samples of clenbuterol were separated by a reversed-phase column (250 mm x 4 mm I.D., particle size 5 microm). The results indicate that the maximum concentration of clenbuterol in muscle was found at 30-45 min after clenbuterol administration (10 mg/kg) and the area under concentration curve (AUC) of clenbuterol in blood and in muscle were 942.75+/-101.92 and 174.81+/-13.03 min microg/mL, respectively. The AUC(muscle)/AUC(blood) was 0.20+/-0.03 representing about 20% of the clenbuterol distributing into the muscle. The elimination half-life of clenbuterol in the blood and muscle were about 2 and 6h, respectively. These results suggest that the protein-unbound concentration of clenbuterol sustained a high level and prolonged elimination in the muscle. The accumulation of clenbuterol might result in some clinical effects when clenbuterol-contaminated meat was consumed.
Chang
Jen-Chih
JC
Institute of Traditional Medicine, School of Medicine, National Yang-Ming University, Taipei, Taiwan.
Lee
Wen-Chuan
WC
Wu
Yu-Tse
YT
Tsai
Tung-Hu
TH
D000818:Animals; D002976:Clenbuterol / Q000008:administration & dosage / Q000097:blood*; D008297:Male; D017551:Microdialysis / Q000379:methods*; D018482:Muscle, Skeletal / Q000187:drug effects / Q000378:metabolism*; D011485:Protein Binding / Q000187:drug effects / Q000502:physiology; D051381:Rats; D017207:Rats, Sprague-Dawley
D002976:Clenbuterol