Fate and residues of 14C-chloramphenicol in laying chickens.
Studies were conducted to determine the metabolic fate of chloramphenicol (CAP) in White Leghorn using the 14C-labelled compound. In one experiment birds were administered orally via intra-crop, a single dose of 100 mg (equivalent to 66 mg kg-1 body weight) of CAP containing 14 microCi 14C-CAP, and its absorption, elimination and distribution in plasma were recorded. Orally dosed 14C-compound was rapidly absorbed, efficiently distributed in plasma and eliminated in excreta (> 70% in 5 hr). After 5 h, CAP equivalent residues in issues were lower than 15 micrograms g-1 for this treatment. In a second experiment birds were given intra-crop dose of either 0.5 or 5 mg of CAP (each dose contained 2.5 microCi 14C-CAP) daily for five consecutive days followed by a seven day withdrawal period and elimination of 14C in excreta and eggs was monitored. More than 95% of the administered 14C was eliminated within the first 24 h after dosing. Radiocarbon (14C) was deposited preferentially in yolks compared to albumen or other tissues. Residues declined when feeding was stopped. Various metabolites were isolated and identified by a combination of TLC, LC, and LC-MS. The main metabolic route of CAP in laying hens appears to be the glucuronidation. Cleavage of the dichloroacetate moiety was only a minor route.
Akhtar
M H
MH
Centre for Food and Animal Research, Research Branch, Agriculture and Agri-Food Canada, Ottawa, Ontario, Canada.
Abo El Sooud
K
K
Shehata
A M
AM
Anwar-ul-Haq
D000284:Administration, Oral; D000818:Animals; D000900:Anti-Bacterial Agents / Q000008:administration & dosage / Q000378:metabolism* / Q000493:pharmacokinetics; D002645:Chickens; D002701:Chloramphenicol / Q000008:administration & dosage / Q000378:metabolism* / Q000493:pharmacokinetics; D002855:Chromatography, Thin Layer; D004350:Drug Residues / Q000009:adverse effects / Q000032:analysis*; D004531:Eggs / Q000032:analysis; D005260:Female; D007408:Intestinal Absorption; D014018:Tissue Distribution
D000900:Anti-Bacterial Agents; D002701:Chloramphenicol