title: Identification of In Vitro Metabolites of Amoxicillin in Human Liver Microsomes by LC-ESI/MS.
abstract: Amoxicillin (AMOX) metabolism in human liver microsomes was studied in vitro using liquid chromatography-mass spectrometry (LC/MS). Amoxicillin was incubated with human liver microsomes along with NADPH, and the reaction mixture was analyzed by LC/MS to obtain the specific metabolic profile of the studied antibiotic drug. Positive electrospray ionization was employed as the ionization source. An ACE C18-column (4.6 mm × 150 mm, 3 μm) was implemented with acetonitrile and water (+0.1 % formic acid) in isocratic mode as the mobile phase at the flow 0.4 mL min-1. The chemical structures of metabolites were proposed on the basis of the accurate mass measurement of the protonated molecule as well as their main product. Six phase I and one phase II metabolites were detected and structurally described. The metabolism of AMOX occurred via oxidation, hydroxylation and oxidative deamination, as well as through combination of these reactions. Compound M7, with glucuronic acid was also observed as phase II metabolite. Neither sulfate nor glutathione conjugates were detected. This study presents novel information about the chemical structure of the potential AMOX metabolites and provides vital data for further pharmacokinetic and in vivo metabolism studies.
authors.affiliation: Department of Environmental Chemistry and Bioanalytics, Faculty of Chemistry, Nicolaus Copernicus University, Gagarin 7 Street, 87-100 Toruń, Poland.
authors.forename: Malgorzata
authors.initials: M
authors.lastname: Szultka
authors.affiliation: Department of Surgery, Collegium Medicum, Nicolaus Copernicus University, St. Joseph Street 53-59, 85-067 Bydgoszcz, Poland.
authors.forename: Rafal
authors.initials: R
authors.lastname: Krzeminski
authors.affiliation: Department of Surgery, Collegium Medicum, Nicolaus Copernicus University, St. Joseph Street 53-59, 85-067 Bydgoszcz, Poland.
authors.forename: Marek
authors.initials: M
authors.lastname: Jackowski
authors.affiliation: Department of Environmental Chemistry and Bioanalytics, Faculty of Chemistry, Nicolaus Copernicus University, Gagarin 7 Street, 87-100 Toruń, Poland.
authors.forename: Boguslaw
authors.initials: B
authors.lastname: Buszewski
keywords: Antibiotic drug; High-performance liquid chromatography; Human liver microsomes; Mass spectrometry
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