Veterinary Drugs Residues: Anthelmintics

Anthelmintics are drugs widely used against intestinal worms. They include several classes, i.e., benzimidazoles and avermectins, and are classified according to their chemical structure and mode of action. Although some of them such as avermectins can be considered safe, others such as benzimidazoles and levamisole are considered toxic to human health. Furthermore, after the ingestion of the anthelmintics, they can be transformed in the host, and some transformation products can be detected in edible tissues. Therefore, international organizations have established maximum residue limits (MRLs) in target tissues, considering the marker residue definition, which may include some of the transformation products generated. Bearing in mind low levels of the MRLs, advanced analytical methods mainly based on liquid chromatography coupled to mass spectrometry detection are currently used for reliable determination of these compounds at trace levels.