title: Residue depletion of amoxicillin and its major metabolites in eggs.
abstract: The depletion of amoxicillin (AMO) and its major metabolites, amoxicilloic acid (AMA) and amoxicillin-diketopiperazine-2',5'-dione (DIKETO) in the albumen, yolk and whole egg was studied after the oral dose of AMO (25 and 50 mg/kg body weight) to laying hens once per day for five consecutive days. Egg samples were prepared by a simple liquid-liquid extraction procedure with acetonitrile and saturated methylene chloride and analysed using liquid chromatography-tandem mass spectrometry. The results showed that AMO, AMA and DIKETO residues were mainly distributed in the yolk, where particularly high concentrations of AMO and DIKETO were found, whereas the albumen contained high concentrations of AMA. This distribution suggested that AMO and DIKETO were depleted slowly in yolk, whereas AMA was depleted slowly in albumen. The amount of AMO residue positively correlated with the dose, and the theoretical withdrawal times, which were calculated based on the residue level falling below a safe limit, were 5.21 and 7.67 days at AMO doses of 25 and 50 mg/kg, respectively. Moreover, the theoretical withdrawal times for all residues in the whole egg were 8.00 and 9.11 days at doses of 25 and 50 mg/kg, respectively. Our findings suggested that 9 days was an appropriate withdrawal time for the use of AMO in laying hens.
authors.affiliation: College of Animal Science and Technology, Yangzhou University, Yangzhou, China.|Key Laboratory for Animal Genetic, Breeding, Reproduction and Molecular Design of Jiangsu Province, Yangzhou, China.
authors.forename: Y-N
authors.initials: YN
authors.lastname: Liu
authors.affiliation: Jiangsu Academy of Agricultural Sciences, Nanjing, China.
authors.forename: M-D
authors.initials: MD
authors.lastname: Pang
authors.affiliation: Jiangsu Academy of Agricultural Sciences, Nanjing, China.|College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, China.
authors.forename: X
authors.initials: X
authors.lastname: Xie
authors.affiliation: College of Animal Science and Technology, Yangzhou University, Yangzhou, China.|Key Laboratory for Animal Genetic, Breeding, Reproduction and Molecular Design of Jiangsu Province, Yangzhou, China.
authors.forename: K-Z
authors.initials: KZ
authors.lastname: Xie
authors.affiliation: College of Animal Science and Technology, Yangzhou University, Yangzhou, China.|Key Laboratory for Animal Genetic, Breeding, Reproduction and Molecular Design of Jiangsu Province, Yangzhou, China.
authors.forename: L-L
authors.initials: LL
authors.lastname: Cui
authors.affiliation: College of Animal Science and Technology, Yangzhou University, Yangzhou, China.|Key Laboratory for Animal Genetic, Breeding, Reproduction and Molecular Design of Jiangsu Province, Yangzhou, China.
authors.forename: Q
authors.initials: Q
authors.lastname: Gao
authors.affiliation: College of Animal Science and Technology, Yangzhou University, Yangzhou, China.|Key Laboratory for Animal Genetic, Breeding, Reproduction and Molecular Design of Jiangsu Province, Yangzhou, China.
authors.forename: J-Y
authors.initials: JY
authors.lastname: Liu
authors.affiliation: College of Animal Science and Technology, Yangzhou University, Yangzhou, China.|Key Laboratory for Animal Genetic, Breeding, Reproduction and Molecular Design of Jiangsu Province, Yangzhou, China.
authors.forename: B
authors.initials: B
authors.lastname: Wang
authors.affiliation: College of Animal Science and Technology, Yangzhou University, Yangzhou, China.|Key Laboratory for Animal Genetic, Breeding, Reproduction and Molecular Design of Jiangsu Province, Yangzhou, China.
authors.forename: Y-Y
authors.initials: YY
authors.lastname: Zhang
authors.affiliation: Jiangsu Academy of Agricultural Sciences, Nanjing, China.
authors.forename: R
authors.initials: R
authors.lastname: Wang
authors.affiliation: College of Animal Science and Technology, Yangzhou University, Yangzhou, China.|Key Laboratory for Animal Genetic, Breeding, Reproduction and Molecular Design of Jiangsu Province, Yangzhou, China.
authors.forename: G-X
authors.initials: GX
authors.lastname: Zhang
authors.affiliation: College of Animal Science and Technology, Yangzhou University, Yangzhou, China.|Key Laboratory for Animal Genetic, Breeding, Reproduction and Molecular Design of Jiangsu Province, Yangzhou, China.
authors.forename: G-J
authors.initials: GJ
authors.lastname: Dai
authors.affiliation: College of Animal Science and Technology, Yangzhou University, Yangzhou, China.|Key Laboratory for Animal Genetic, Breeding, Reproduction and Molecular Design of Jiangsu Province, Yangzhou, China.
authors.forename: J-Y
authors.initials: JY
authors.lastname: Wang
mesh_terms: D000658:Amoxicillin / Q000378:metabolism*; D000818:Animals; D000900:Anti-Bacterial Agents / Q000032:analysis / Q000378:metabolism; D002645:Chickens / Q000378:metabolism*; D004350:Drug Residues / Q000032:analysis* / Q000378:metabolism*; D004531:Eggs / Q000032:analysis*; D005260:Female
chemical_list: D000900:Anti-Bacterial Agents; D000658:Amoxicillin