[Distribution of Rifamycin SV in de Bovine Tissues Following Intramammary Administration of Rifamastene (author's transl)].

Depending on the physiological activity of the udder, from 4 to 95 per cent of the rifamycin SV administered by intrammary injection are absorbed from the udder and approximately 95 per cent of the absorbed rifamycin SV are excreted through the liver. The rifamycin SV eliminated in the faeces will lose its microbiological activity more or less rapidly, depending on the temperature and oxygen tension. Accumulation of rifamycin SV in the meat and organs will not occur on intramammary administration of this antibiotic. A balance between absorption and excretion is attained within sixty minutes after intramammary administration of Rifamastene in cattle. The maximum rifamycin SV concentrations determined in the serum, bile and urine were 0.12, 18.2 and 0.32 mug/ml respectively. Van Schothorst's S. lutea kidney test which is required by law in the Netherlands, was negative in every case.