Dapsone Residues in Milk and the Organs of Cows After Intramammary and Intrauterine Administration

Abstract

Dapsone was injected into the udders of lactating and culled dairy cows and the concentration and persistence of the drug in milk and body organs were determined. The drug appeared to be well distributed in the udder and was quickly eliminated, chiefly by absorption into the general blood circulation. Residues in milk were not detected 48, 56 and 60 h after treatment with preparations containing 0·55, 1·0 and 3·0 g dapsone, respectively. When a preparation containing 1·0 g dapsone was injected into a single quarter of the udder of each of several cows, residues were not found in any body organ 48 h after treatment; when two or more quarters were injected, residues were detected in the kidney, urine and bile. Following intrauterine administration of a commercial preparation containing 1·0 g dapsone, the drug was detected in the serum during 24 h and in the milk during 12 h. The presently available microbiological assay methods for the detection of antibiotic residues are unsuitable for the assay of dapsone.