Antiparasitics

Changed on: 10.05.2019

Antiparasitics are pharmaceuticals used for the treatment of endo- and ectoparasitic infections. Endoparasites live inside the host’s body (e.g. worms), while ectoparasites can be found on the body’s surface (e.g. ticks, fleas, mites). Many antiparasitic drugs can be linked to the following chemical compound categories:

Avermectine: used for both endo- and ectoparasites
Benzimidazoles and imidazothiazoles (Levamisole): for endoparasites
Organophosphorous compounds and pyrethroides: for ectoparasites

More information

Antiparasitics are pharmaceuticals used for the treatment of endo- and ectoparasitic infections. Endoparasites live inside the host’s body (e.g. worms), while ectoparasites can be found on the body’s surface (e.g. ticks, fleas, mites). Many antiparasitic drugs can be linked to the following chemical compound categories:

Avermectine: used for both endo- and ectoparasites
Benzimidazoles and imidazothiazoles (Levamisole): for endoparasites
Organophosphorous compounds and pyrethroides: for ectoparasites

More information

Substance Categories

Avermectines (incl. Milbemycines such as Moxidectin) with no antibacterial effect have a macrocyclic lacton in their molecular structure as their common feature. They bind to glutamate-activated chloride channels, typical for invertebrates such as nematodes and arthropods. This increases the membrane permeability in muscle and nerve cells, inhibiting their activity and killing off the parasites. Avermectines are metabolic products from Actinomycetales (Streptomyces) that are subsequently partly chemically modified. Abamectin, one representative of the Avermectines group, is used as a pesticide as a result of its insecticide and acaricide effects.

Benzimidazoles are anthelmintics (drugs used treat parasitic worm infections), which work by binding to specific proteins of the parasitic cells, so-called tubulins. This interrupts the formation of microtubuli, affecting important structural (cytoskeleton) and functional (intake and intracellular transport of nutrients) cell processes, which leads to the killing of the worms and the defecating of them a few days later. The common feature in this substance category is a Benzimidole core in the substances’ molecular structure.

Levamisole is the L-isomer of Tetramisole, which contains the L and R forms in equal parts. Only the L-isomer has an anthelmintic effect, affecting the cholinergic stimuli, resulting in the paralysing and subsequently killing of the parasite.

Examination Spectrum and Analysis Methods

The Department for Veterinary Medicine, Hormones and Contaminants at the Institute of Food Safety Vienna analyses antiparasitics in the substance categories Avermectine, Benzimidazole, incl. Levamisole and salicylic acid /phenole derivates (incl. salicylic anilides)/Benzol sulfonamides on a routine basis in animal tissue and milk and is also a National Reference Laboratory for these examinations.

Regular participation in international round-robin tests and workshops held by the EU Reference Laboratory (EURL) for antiparasitics in Berlin ensures the quality of results and the continuous development of analysis methods to state-of-the-art levels of technology and research.
The individual substance categories are examined using a specific analysis method (in terms of sample preparation and measuring) for each Group:

Avermectine

Avermectine

Abamectine (Avermectin B1a)
Doramectine
Emamectine B1a
Eprinomectine
Ivermectine B1a (22,23-Dihydroavermectine B1a)
Moxidectine

Analysis method: HPLC with post-column fluorescence derivatization (HPLC/FLD)

Benzimidazoles incl. Levamisole

Benzimidazoles incl. Levamisole

Albendazole
Albendazole sulfone
Albendazole-2-aminosulfone
Albendazole sulfoxide
Febantel
Fenbendazole
Flubendazole and Aminoflubendazole
Levamisole
Mebendazole, Hydroxymebendazole and Aminomebendazole
Nocodazole
Oxfendazole
Oxfendazole sulfone
Oxibendazole
Parbendazole
Thiabendazole and 5-Hydroxythiabendazole
Triclabendazole
Triclabendazole sulfoxide
Triclabendazole sulfone
Ketotriclabendazole

Analysis method: HPLC with tandem mass spectrometry (LC/MSMS)

Salicylic Acid/Phenole derivates (incl. salicylic anilides)/Benzole sulfonamides

Salicylic Acid/Phenole derivates (incl. salicylic anilides)/Benzole sulfonamides

Clorsulon
Closantel
Nitroxinil
Oxyclozanide
Rafoxanide

Analysis method: HPLC with tandem mass spectrometry (LC/MSMS) 

A chemiluminescence immunoassay is used additionally for the more rapid screening of Avermectines and Benzimidazoles incl. Levamisole in milk.

Legal Regulations

There are limits for animal tissue (muscle, fat, liver and kidneys) and in parts for milk and eggs (Flubendazol) that are specified in Regulation (EU) No 37/2010, which defines the maximum levels for veterinary drug residues in food of animal origin. These limits are lower for milk than other matrices – similar to most other pharmaceuticals. The administration of some antiparasitics (e.g. Mebendazole) to animals farmed for milk production is strictly prohibited: do not use for animals the milk of which is intended for human consumption.” Blood and urine are not covered by the Regulation above.

Legal Basis

Commission Regulation (EU) No 37/2010 of 22 December, 2009 on pharmacologically active substances and their classification regarding maximum residue limits in foodstuffs of animal origin (OJ EU No. L 15 of 20 January 2010)

 

 

 

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