Ivermectin residues in milk of lactating donkey (Equus asinus): current regulation and challenges for the future

Ivermectin (IVM) is a macrocyclic disaccharide anthelmintic agent with broad-spectrum antiparasitic action. It is used for controlling internal and external parasites in food-producing animals (bovine, swine and equine species), including donkey. This drug is included in Council Regulation (EEC) 2377/90, annex I, with Maximum Residue Limit (MRL) ranging from 15 to 100???g?kg^?1 depending on the species. The pharmacokinetic characteristics of IVM mainly depend on the animal species, formulation and route of administration. Due to its high lipophilicity it accumulates in milk of food producing animals. Detailed IVM pharmacokinetic studies were carried out for horse, pig, cattle, sheep, and goat, but there is lack of information for asinine species. Consequently, the absence of ??label milk withdrawal time?? and MRLs in donkey??s milk indicates that IVM should not be used in lactating animals. On the contrary, information about IVM residues in milk would be of paramount importance in view of the fact that donkey??s milk is a suggested substitute for infants suffering from hypersensitivity to cow??s, sheep??s and goat??s milk protein or from multiple hypersensitivity. European legislation does not explicitly state that an MRL should be determined for every target species; however it??s interpretation led to MRLs being adopted for each species and each foodstuff. Although IVM is approved for use in all lactating animal species the possibility of an illegal use should be considered. In this paper, the problems arising from IVM administration in lactating donkey are analysed. A particular attention is paid for the existing legislation and some proposals are suggested for regulatory framework formulation.