To explore the distribution and elimination of thiabendazole and its metabolite 5-hydrothiabendazole residues in the hens tissues including liver, muscle, heart, fat, as well as in eggs.Laying hens were orally administred thiabendazole for 5 consecutive days (100mg per hen daily) and then the hens were sacrificed at the times of 1 day, 3 days, 5 days and 7 days after the end of treatment. Eggs, liver,muscle,fat and heart tissues were collected and homogenized. The samples were extracted by acetonitrile, further concentrated and purified by an Oasis MCX cartridge, and then the contents of thiabendazole and 5-hydrothiabendazole in tissue homogenates determinated by liquid chromatography electrospray ionisation tandem mass spectrometry (UPLC-ESI-MS/MS).The major residues in the tissue homogenates was 5-hydroxythiabendazole, with more higher concentrations than thiabendazole. Egg samples presented the large majority of both drug residues. For the tissue homogenates,the total concentrations of thiabendazole and 5-hydrothiabendazole residues followed the order of liver > heart > muscle > fat at 1 day after the treatment. The withdrawal period of thiabendazole for eggs was about 7 days.Distribution and elimination of thiabendazole and its metabolite residues in laying hens were primarily studied in this study.
