Simplified LC-MS/MS method enabling the determination of azithromycin in human plasma after a low 100mg dose administration

J Pharm Biomed Anal. 2014 Nov;100:184-189. doi: 10.1016/j.jpba.2014.07.015. Epub 2014 Aug 8.


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.

Keywords: Azithromycin; Liquid chromatography/tandem mass spectrometry; Metabolite back-conversion; Method validation; Pharmacokinetics.

Publication types

  • Research Support, Non-U.S. Gov't
  • Validation Study

MeSH terms

  • Administration, Oral
  • Anti-Bacterial Agents / administration & dosage*
  • Anti-Bacterial Agents / blood*
  • Anti-Bacterial Agents / pharmacokinetics
  • Azithromycin / administration & dosage*
  • Azithromycin / blood*
  • Azithromycin / pharmacokinetics
  • Biotransformation
  • Calibration
  • Chromatography, Liquid / methods*
  • Humans
  • Linear Models
  • Liquid-Liquid Extraction
  • Predictive Value of Tests
  • Reference Standards
  • Reproducibility of Results
  • Spectrometry, Mass, Electrospray Ionization / methods*
  • Tandem Mass Spectrometry / methods*


  • Anti-Bacterial Agents
  • Azithromycin