Bioavailability, pharmacokinetics and residues of chloramphenicol in the chicken.
The pharmacokinetic properties of chloramphenicol were determined in broiler chickens after two single oral doses (30 and 50 mg/kg body weight) and after a single intravenous (i.v.) dose (30 mg/kg body weight). After oral and i.v. administration, the plasma concentration-time graph was characteristic of a two-compartment open model. After oral administration (30 and 50 mg/kg), chloramphenicol was absorbed rapidly (time to maximal concentration of 0.72 or 0.60 h) and eliminated with a mean half-life (t1/2 beta) of 6.87 or 7.41 h, respectively. The bioavailability was 29% at 30 mg/kg chloramphenicol and 38% at 50 mg/kg chloramphenicol. Concentrations greater than 5 micrograms/ml were achieved at 15 min and persisted up to 2 or 4 h post-administration, respectively. Statistically significant differences between the two routes of administration were found for the pharmacokinetic variables, half-lives of both distribution and elimination phases (t1/2 alpha, t1/2 beta) and apparent volume of distribution [Vd(area)]. The mean t1/2 beta of chloramphenicol and i.v. administration was 5.23 h. Chloramphenicol was extensively metabolized into dehydrochloramphenicol (DH-CAP), nitrophenylaminopropanedione (NPAP) and nitroso-chloramphenicol (NO-CAP) derivatives. Residues of chloramphenicol (CAP) and the three metabolites DH-CAP, NPAP and NO-CAP in kidney, liver and muscle were measured in chickens that received an oral dose of 50 mg/kg once daily for 4 days. The results indicate that CAP and DH-CAP residues were cleared slowly and were at or below the detection limit of 0.005 microgram/ml within 12 days after dosing. However, at the time of slaughter (12 days), the NPAP and NO-CAP residues were detected in the tissue.
Anadón
A
A
CSIC, Department of Toxicology, Faculty of Veterinary Medicine, Universidad Complutense, Madrid, Spain.
Bringas
P
P
Martinez-Larrañaga
M R
MR
Diaz
M J
MJ
D000284:Administration, Oral; D000818:Animals; D001682:Biological Availability; D002645:Chickens / Q000378:metabolism*; D002701:Chloramphenicol / Q000008:administration & dosage / Q000493:pharmacokinetics*; D002851:Chromatography, High Pressure Liquid / Q000662:veterinary; D004350:Drug Residues / Q000378:metabolism*; D006207:Half-Life; D007275:Injections, Intravenous / Q000662:veterinary; D008297:Male; D014018:Tissue Distribution
D002701:Chloramphenicol