Milk excretion of antiparasitic drugs in dairy sheep: Residues in milk-derived products

IMPERIALE, F.; PIS, A.; SALLOVITZ, J.; LIFSCHITZ, A.; LANUSSE C.

Mar del Plata, Argentina

Congreso; XXXVII Reunión anual de la Asociación Argentina de Farmacología Experimental; 2005

Asociación Argentina de Farmacología Experimental

Ivermectin (IVM), eprinomectin (EPM) and moxidectin (MXD) are broad-spectrum endectocide antiparasitic drugs extensively used in food-producing animals. The patterns of IVM, EPM and MXD excretion in milk were comparatively characterized following their subcutaneous (IVM, MXD) (200 mg.kg-1) and topical administration (EPM) (500 mg.kg-1) to lactating dairy sheep. A pool of milk collected from all the animals in each experimental group was used for cheese elaboration. IVM, EPM and MXD concentrations were measured in milk and dairy products using an HPLC-based methodology with fluorescence detection. Residual concentrations of these compounds were recovered in milk up to 30 (IVM), 15 (EPM) and 35 (MXD) days post-treatment. During milk processing a high proportion of parent drug was found in the curd. IVM, EPM and MXD concentrations in the elaborated cheese tended to increase during the ripening period, reaching the highest residual level at 40 days cheese maturation. The scientific evidences shown here, indicate that IVM, EPM and MXD residues in cheese are between 3 and 5-fold higher than those measured in the milk used for its elaboration. The impact of these residual drug concentrations in milk-derived product on human safety are under evaluation.