Tracer Dyes Food Green No. 4 and Food Blue No. 3 in Antibiotic and Chemotherapeutic Preparations for Intramammary Application Iv

Comparison has been made between Food Green No. 4 and Food Blue No. 3 as tracer dyes for indirect detection of the drugs in milk after intramammary application of a number of commonly used preparations containing antibiotics and chemotherapeutic agents.The tracer dyes had no effect on the stability of the preparations containing penicillin, penicillin ester, and sulphonamide (I, II, III, V and VI) ; after six months’ storage at room temperature, 75 to 100 per cent of the drugs could be recovered. The Oxytetracycline content in preparation IV recovered by 70 to 100 per cent after two months. There were great differences in the irritating effect of the various preparations, as determined by the cell counts of the milk, but the addition of tracer dye did not alter this effect. A direct relationship was demonstrated between concentrations of, on the one hand, tracer dye and, on the other hand, penicillin (preparations I, II, and III), Oxytetracycline (preparation IV) and sulphonamide (preparations V and VI) in milk from ten treated cows.In all quarter samples tracer dye could be demonstrated for just as long as the drugs, and often one or two milkings longer. Thus the experiments confirm the great certainty with which triphenylmethane dyes can reveal indirectly the presence of very small residues of antibiotics and sulphonamides in the milk after intramammary infusion.