DISPOSITION OF SULFONAMIDES IN FOOD-PRODUCING ANIMALS - CONCENTRATIONS OF SULFAMETHAZINE AND ITS METABOLITES IN PLASMA, URINE, AND TISSUES OF LAMBS FOLLOWING INTRAVENOUS ADMINISTRATION

Abstract

A sensitive, precise, and efficient analytical method for sulfamethazine in the liver, kidney, heart, skeletal muscle, and fat of lambs is reported. The method involves freezing cubed tissue in liquid nitrogen, powdering the frozen tissue in a liquid nitrogen-cooled blender, and extracting the tissue on a sodium sulfate column with chloroform:acetone. A thin-layer chromatographic procedure capable of separating and quantitating sulfamethazine and 3 metabolites (acetyl, hydroxylated, and polar conjugate(s) in lamb urine is also reported. Sulfamethazine was administered intravenously (107.25 mg/kg body weight) to 14 cross-bred ewe lambs. The concentration of sulfamethazine in plasma and tissue..