title: High resolution mass spectrometry in the identification of transformation products and metabolites from β-lactam antibiotics in thermally treated milk.
abstract: Antibiotics such as β-lactam derivatives (penicillins and cephalosporins) are frequently used in veterinary medicine. The presence of these antibiotics together with their metabolites and/or products produced in subsequent treatments at which milk is submitted (sterilization, pasteurization), may be responsible for bacterial resistance, allergy and/or toxicity on sensitive individuals. In this study, liquid chromatography coupled with high resolution mass spectrometry (LC-HRMS) is used to identify transformation products (TPs) from four β-lactam antibiotics (amoxicillin (AMOX), cephapirin (PIR), ceftiofur (TIO) and penicillin G (PENG)) in thermally treated cow milk. In addition, milk from cows medicated with PENG has also been analogously treated and studied. The detected TPs come mainly from hydrolysis and decarboxylation reactions. Products more strongly degraded respect to parent compounds (of lower molecular weight) were obtained after treating milk at higher temperatures. Products identified in milk from cows medicated with PENG have been classified as TPs when coming from chemical/thermal degradation, and metabolites when resulting from the biological drug metabolism. While TPs are the result of hydrolysis and decarboxylation processes, as already indicated, an enzymatic conjugation with amino acids is suggested to be involved in the formation of metabolites.
authors.affiliation: Department of Analytical Chemistry, Campus de l'Alimentació de Torribera, University of Barcelona, Avda. Prat de la Riba, 171, 08921 Sta. Coloma de Gramenet, Barcelona, Spain.
authors.forename: A
authors.initials: A
authors.lastname: Junza
authors.affiliation: Department of Analytical Chemistry, Campus de l'Alimentació de Torribera, University of Barcelona, Avda. Prat de la Riba, 171, 08921 Sta. Coloma de Gramenet, Barcelona, Spain.
authors.forename: A
authors.initials: A
authors.lastname: Montané
authors.affiliation: Department of Analytical Chemistry, University of Barcelona, Martí i Franquès, 1-11, 08028 Barcelona, Spain.
authors.forename: J
authors.initials: J
authors.lastname: Barbosa
authors.affiliation: Department of Pharmacology and Therapeutic Chemistry, Campus de l'Alimentació de Torribera, University of Barcelona, Avda. Prat de la Riba, 171, 08921 Sta. Coloma de Gramenet, Barcelona, Spain. Electronic address: cminguillon@ub.edu.
authors.forename: C
authors.initials: C
authors.lastname: Minguillón
authors.affiliation: Department of Analytical Chemistry, Campus de l'Alimentació de Torribera, University of Barcelona, Avda. Prat de la Riba, 171, 08921 Sta. Coloma de Gramenet, Barcelona, Spain. Electronic address: dolores.barron@ub.edu.
authors.forename: D
authors.initials: D
authors.lastname: Barrón
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000032:analysis* / Q000737:chemistry / Q000378:metabolism; D002853:Chromatography, Liquid / Q000379:methods; D006801:Humans; D013058:Mass Spectrometry / Q000295:instrumentation / Q000379:methods*; D008892:Milk / Q000737:chemistry*; D013696:Temperature; D047090:beta-Lactams / Q000032:analysis* / Q000737:chemistry / Q000378:metabolism
chemical_list: D000900:Anti-Bacterial Agents; D047090:beta-Lactams
keywords: LC-LTQ-Orbitrap; Metabolites; Milk; Thermal treatment; Transformation products; β-Lactams