title: Metabolic pathways of anthelmintic drug monepantel in sheep and in its parasite (Haemonchus contortus).
abstract: Monepantel (MOP) is a new anthelmintic drug intended for the treatment and control of gastrointestinal roundworms (nematodes) infection and associated disease in sheep. The aim of our study was to find out metabolic pathways of MOP in sheep in vivo and in its parasite Haemonchus contortus ex vivo. MOP biotransformation in two H. contortus strains with different sensitivity to anthelmintics was also compared. Ultra high-performance liquid chromatography with tandem mass spectrometry (UHPLC-MS/MS) technique is used for the identification of MOP metabolites in ovine urine, faeces, and nematodes. MOP biotransformation study in sheep in vivo led to the identification of 13 MOP metabolites; 7 of them have not been described previously in in vitro study. The study of MOP biotransformation in H. contorus ex vivo reveals four MOP metabolites. The nitrile hydrolysis as a new biotransformation pathway in helminths ex vivo is reported here for the first time. Unlike sheep, H. contorus nematodes are not able to metabolize MOP via phase II biotransformation. Nematodes of resistant White river (WR) strain form more types of MOP metabolites than nematodes of sensitive inbred susceptible Edinburgh (ISE) strain. Based on obtained results, schemes of metabolic pathways of MOP in sheep and nematodes are proposed.
authors.affiliation: Department of Biochemical Sciences, Faculty of Pharmacy in Hradec Králové, Charles University in Prague, Heyrovského 1203, 500 05, Hradec Králové, Czech Republic.
authors.forename: Lucie
authors.initials: L
authors.lastname: Stuchlíková
authors.forename: Robert
authors.initials: R
authors.lastname: Jirásko
authors.forename: Ivan
authors.initials: I
authors.lastname: Vokřál
authors.forename: Martin
authors.initials: M
authors.lastname: Valát
authors.forename: Jiří
authors.initials: J
authors.lastname: Lamka
authors.forename: Barbora
authors.initials: B
authors.lastname: Szotáková
authors.forename: Michal
authors.initials: M
authors.lastname: Holčapek
authors.forename: Lenka
authors.initials: L
authors.lastname: Skálová
mesh_terms: D000607:Aminoacetonitrile / Q000031:analogs & derivatives* / Q000032:analysis / Q000378:metabolism; D000818:Animals; D000871:Anthelmintics / Q000032:analysis / Q000378:metabolism*; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D006189:Haemonchus / Q000187:drug effects / Q000378:metabolism*; D008297:Male; D012756:Sheep; D053719:Tandem Mass Spectrometry / Q000379:methods
chemical_list: D000871:Anthelmintics; D000607:Aminoacetonitrile; C533978:monepantel
keywords: UHPLC-MS; amino-acetonitrile derivatives; biotransformation; mass spectrometry; nematodes