Rapid absorption of diclofenac and acetaminophen after their oral administration to cattle.
The oral pharmacokinetics of diclofenac (DF) were evaluated in cattle by analyzing plasma concentration-time data after its intravenous and oral administration in order to propose the oral administration of DF as effective route to avoid long withdraw period. DF was intravenously and orally administered at 1 mg/kg to cattle using a crossover design with a 4-week washout period. Plasma concentrations of DF were determined by a HPLC analysis. The mean absorption time (MAT) and absorption half-life (t1/2ka) were 1.61 ± 0.61 and 1.51 ± 0.38 hr, respectively, and bioavailability was nearly 100%. The oral pharmacokinetics of acetaminophen (AAP) were also evaluated in cattle. Plasma concentrations of AAP were determined by a HPLC analysis. MAT and t1/2kawere 2.85 ± 0.93 and 1.53 ± 0.28 hr, respectively, and bioavailability was approximately 70%. In conclusion, the results of the present study indicate that DF and AAP are rapidly absorbed from the forestomach of cattle. Therefore, the appropriate efficacies of these drugs may be achieved via their oral administration, even in cattle.
Laboratory of Veterinary Pharmacology, Department of Veterinary Medicine, Tokyo University of Agriculture and Technology, Fuchu, Tokyo 183-8509, Japan.
Akiyo
A
Sawaguchi
Kazuaki
K
Sasaki
Keisuke
K
Miyanaga
Mitsuhiro
M
Nakayama
Masato
M
Nagasue
Minoru
M
Shimoda
D000082:Acetaminophen / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics*; D000284:Administration, Oral; D018712:Analgesics, Non-Narcotic / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics*; D000818:Animals; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics*; D002417:Cattle / Q000097:blood / Q000378:metabolism; D004008:Diclofenac / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics*; D007275:Injections, Intravenous / Q000662:veterinary; D008297:Male
D018712:Analgesics, Non-Narcotic; D000894:Anti-Inflammatory Agents, Non-Steroidal; D004008:Diclofenac; D000082:Acetaminophen