title: Comprehensive Analysis of Tiamulin Metabolites in Various Species of Farm Animals Using Ultra-High-Performance Liquid Chromatography Coupled to Quadrupole/Time-of-Flight.
abstract: Tiamulin is an antimicrobial widely used in veterinary practice to treat dysentery and pneumonia in pigs and poultry. However, knowledge about the metabolism of tiamulin is very limited in farm animals. To better understand the biotransformation of tiamulin, in the present study, in vitro and in vivo metabolites of tiamulin in rats, chickens, swine, goats, and cows were identified and elucidated using ultra-high performance liquid chromatography coupled to quadrupole/time-of-flight. As a result, a total of 26 metabolites of tiamulin, identified in vitro and in vivo, and majority of metabolites were revealed for the first time. In all farm animals, tiamulin undergoes phase I metabolic routes of hydroxylation in the mutilin part (the ring system), S-oxidation and N-deethylation on side chain, and no phase II metabolite was detected. Among these, 2β- and 8α-hydroxylation and N-deethylation were the main metabolic pathways of tiamulin in farm animals. In addition, we have put forward that 8a-hydroxy-tiamulin and 8a-hydroxy-N-deethyl-tiamulin could be hydroxylated into 8a-hydroxy-mutilin, the marker residue of tiamulin in swine. Furthermore, a significant interspecies difference was observed on the metabolism of tiamulin among various farm animals. The possible marker residues for tiamulin in swine were 8α-hydroxy-tiamulin, N-deethyl-tiamulin, and 8α-hydroxy-N-deethyl-tiamulin, which were consistent with the hypothesis proposed by the European Agency for the Evaluation of Medicinal Products. However, results in present study indicated that three metabolites (2β-hydroxy-tiamulin, N-deethyl-tiamulin, and 2β-hydroxy-N-deethyl-tiamulin) of tiamulin in chickens had larger yields, which implied that 2β-hydroxy-mutilin or N-deethyl-tiamulin was more likely to be regarded as the potential marker residue of tiamulin in chickens.
authors.affiliation: College of Veterinary Medicine and Beijing Laboratory for Food Quality and Safety, Beijing Key Laboratory of Detection Technology for Animal-Derived Food Safety, National Reference Laboratory of Veterinary Drug Residues, China Agricultural University , Beijing 100193, People's Republic of China.
authors.forename: Feifei
authors.initials: F
authors.lastname: Sun
authors.affiliation: Bee Research Institute and Bee Product Quality Supervision and Testing Center, Laboratory of Risk Assessment for Quality and Safety of Bee Products, Ministry of Agriculture, Chinese Academy of Agricultural Sciences , Beijing 100093, People's Republic of China.
authors.forename: Shupeng
authors.initials: S
authors.lastname: Yang
authors.affiliation: College of Veterinary Medicine and Beijing Laboratory for Food Quality and Safety, Beijing Key Laboratory of Detection Technology for Animal-Derived Food Safety, National Reference Laboratory of Veterinary Drug Residues, China Agricultural University , Beijing 100193, People's Republic of China.
authors.forename: Huiyan
authors.initials: H
authors.lastname: Zhang
authors.affiliation: Bee Research Institute and Bee Product Quality Supervision and Testing Center, Laboratory of Risk Assessment for Quality and Safety of Bee Products, Ministry of Agriculture, Chinese Academy of Agricultural Sciences , Beijing 100093, People's Republic of China.
authors.forename: Jinhui
authors.initials: J
authors.lastname: Zhou
authors.affiliation: Bee Research Institute and Bee Product Quality Supervision and Testing Center, Laboratory of Risk Assessment for Quality and Safety of Bee Products, Ministry of Agriculture, Chinese Academy of Agricultural Sciences , Beijing 100093, People's Republic of China.
authors.forename: Yi
authors.initials: Y
authors.lastname: Li
authors.affiliation: Bee Research Institute and Bee Product Quality Supervision and Testing Center, Laboratory of Risk Assessment for Quality and Safety of Bee Products, Ministry of Agriculture, Chinese Academy of Agricultural Sciences , Beijing 100093, People's Republic of China.
authors.forename: Jinzhen
authors.initials: J
authors.lastname: Zhang
authors.affiliation: Bee Research Institute and Bee Product Quality Supervision and Testing Center, Laboratory of Risk Assessment for Quality and Safety of Bee Products, Ministry of Agriculture, Chinese Academy of Agricultural Sciences , Beijing 100093, People's Republic of China.
authors.forename: Yue
authors.initials: Y
authors.lastname: Jin
authors.affiliation: College of Veterinary Medicine and Beijing Laboratory for Food Quality and Safety, Beijing Key Laboratory of Detection Technology for Animal-Derived Food Safety, National Reference Laboratory of Veterinary Drug Residues, China Agricultural University , Beijing 100193, People's Republic of China.
authors.forename: Zhanhui
authors.identifier: http://orcid.org/0000-0002-0167-9559
authors.initials: Z
authors.lastname: Wang
authors.affiliation: College of Life Science, Yantai University , Yantai, Shandong 264005, P. R. China.
authors.forename: Yanshen
authors.initials: Y
authors.lastname: Li
authors.affiliation: College of Veterinary Medicine and Beijing Laboratory for Food Quality and Safety, Beijing Key Laboratory of Detection Technology for Animal-Derived Food Safety, National Reference Laboratory of Veterinary Drug Residues, China Agricultural University , Beijing 100193, People's Republic of China.
authors.forename: Jianzhong
authors.initials: J
authors.lastname: Shen
authors.affiliation: College of Veterinary Medicine and Beijing Laboratory for Food Quality and Safety, Beijing Key Laboratory of Detection Technology for Animal-Derived Food Safety, National Reference Laboratory of Veterinary Drug Residues, China Agricultural University , Beijing 100193, People's Republic of China.
authors.forename: Suxia
authors.initials: S
authors.lastname: Zhang
authors.affiliation: College of Veterinary Medicine and Beijing Laboratory for Food Quality and Safety, Beijing Key Laboratory of Detection Technology for Animal-Derived Food Safety, National Reference Laboratory of Veterinary Drug Residues, China Agricultural University , Beijing 100193, People's Republic of China.
authors.forename: Xingyuan
authors.identifier: http://orcid.org/0000-0003-2063-6260
authors.initials: X
authors.lastname: Cao
mesh_terms: D000818:Animals; D000829:Animals, Domestic / Q000378:metabolism*; D000890:Anti-Infective Agents / Q000032:analysis* / Q000378:metabolism*; D002417:Cattle / Q000378:metabolism; D002645:Chickens / Q000378:metabolism; D002851:Chromatography, High Pressure Liquid / Q000295:instrumentation / Q000379:methods*; D004224:Diterpenes / Q000032:analysis / Q000378:metabolism; D005260:Female; D006041:Goats / Q000378:metabolism; D008297:Male; D013058:Mass Spectrometry; D008862:Microsomes, Liver / Q000737:chemistry / Q000378:metabolism; D010084:Oxidation-Reduction; D051381:Rats; D017208:Rats, Wistar / Q000378:metabolism; D013552:Swine / Q000378:metabolism
chemical_list: D000890:Anti-Infective Agents; D004224:Diterpenes; C014224:tiamulin
keywords: UHPLC−Q/TOF; comparative metabolism; farm animals; in vivo; liver microsomes; tiamulin