DISPOSITION OF SULFONAMIDES IN FOOD-PRODUCING ANIMALS - PHARMACOKINETICS OF SULFAMETHAZINE IN LAMBS

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  • 1 January 1977
    • journal article
    • research article
    • Vol. 38  (7) , 967-972
Abstract
Previously reported plasma and urine concentrations of unchanged sulfamethazine and 3 metabolites following i.v. administration of sodium sulfamethazine to young ewe lambs were fitted to a linear pharmacokinetic model in which sulfamethazine itself obeyed 1-compartment pharmacokinetics. The average rate constant for overall elimination of sulfamethazine was 0.096 .+-. 0.023 h-1, corresponding to a biological half-life of 7.2 .+-. 1.7 h. The results of residue analysis of 8 tissues obtained at slaughter showed that tissue and plasma concentrations and urine output of unchanged sulfamethazine fell parallel throughout the experiment. Determination of the plasma concentration or urinary output of sulfamethazine can apparently be substituted for tissue residue analysis to determine contamination of carcasses above specified tolerance limits.