Ceftiofur sodium: absorption, distribution, metabolism, and excretion in target animals and its determination by high-performance liquid chromatography
1996
Beconi-Barker, M.G. | Roof, R.D. | Vidmar, T.J. | Hornish, R.E. | Smith, E.B. | Gatchell, C.L. | Gilbertson, T.J.
After intramuscular injections of [14C]-ceftiofur sodium to beef, dairy cattle, swine and sheep, the radiolabeled cephalosporin was absorbed rapidly into the blood and eliminated mostly in the urine (>65% for all species). In all species, the tissue where highest residue concentrations were observed at 12 h after the last dose was the kidney. The major metabolite of ceftiofur was desfuroylceftiofur (DFC), which is microbiologically active, and was found conjugated to cysteine, glutathione and plasma and tissue proteins. An HPLC method was developed and validated for the determination and quantitation of ceftiofur-related metabolites that have the potential to be microbiologically active in bovine and swine muscle, kidney, liver and fat and sheep muscle and kidney. This method is based on the cleavage of the disulfide and/or thioester bonds between the metabolites and their conjugate sulfur containing moiety using dithioerythritol to yield DFC, which is then stabilized by derivatizing to desfuroylceftiofur acetamide.
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