title: Simplified LC-MS/MS method enabling the determination of azithromycin in human plasma after a low 100mg dose administration.
abstract: A sensitive liquid chromatographic-tandem mass spectrometric method was developed and validated to study the pharmacokinetics of a low dose of azithromycin in human plasma. The sample preparation was based on liquid-liquid extraction with the low volume of methyl t-butyl ether. The chromatographic separation was performed on a Symmetry C18 column (50×2.1mm, 3.5μm). Gradient elution with ammonium acetate-acetonitrile and ammonium acetate-methanol was applied. Positive electrospray ionisation tandem mass spectrometry in the multiple reaction monitoring mode was used for the detection of azithromycin. The influence of a major metabolite, including the possibility of its back-conversion, on the quantification of azithromycin was evaluated. Isotope labelled azithromycin was used as the internal standard. The calibration curve was linear in the range of 0.5-250.0ng/mL. The new validated method was successfully applied to a pharmacokinetic study in humans following a single 100mg oral dose.
authors.affiliation: Pharmaceutical Research Institute, Pharmacology Department, 8 Rydygiera, 01-793 Warsaw, Poland. Electronic address: m.filist@ifarm.eu.
authors.forename: Monika
authors.initials: M
authors.lastname: Filist
authors.affiliation: Pharmaceutical Research Institute, Pharmacology Department, 8 Rydygiera, 01-793 Warsaw, Poland.
authors.forename: Katarzyna
authors.initials: K
authors.lastname: Buś-Kwaśnik
authors.affiliation: Pharmaceutical Research Institute, Pharmacology Department, 8 Rydygiera, 01-793 Warsaw, Poland.
authors.forename: Hanna
authors.initials: H
authors.lastname: Ksycińska
authors.affiliation: Pharmaceutical Research Institute, Pharmacology Department, 8 Rydygiera, 01-793 Warsaw, Poland.
authors.forename: Piotr J
authors.initials: PJ
authors.lastname: Rudzki
mesh_terms: D000284:Administration, Oral; D000900:Anti-Bacterial Agents / Q000008:administration & dosage* / Q000097:blood* / Q000493:pharmacokinetics; D017963:Azithromycin / Q000008:administration & dosage* / Q000097:blood* / Q000493:pharmacokinetics; D001711:Biotransformation; D002138:Calibration; D002853:Chromatography, Liquid / Q000379:methods*; D006801:Humans; D016014:Linear Models; D059625:Liquid-Liquid Extraction; D011237:Predictive Value of Tests; D012015:Reference Standards; D015203:Reproducibility of Results; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*; D053719:Tandem Mass Spectrometry / Q000379:methods*
chemical_list: D000900:Anti-Bacterial Agents; D017963:Azithromycin
keywords: Azithromycin; Liquid chromatography/tandem mass spectrometry; Metabolite back-conversion; Method validation; Pharmacokinetics