Ocular pharmacokinetic study following single and multiple azithromycin administrations in pigmented rabbits

Curr Eye Res. 2008 Feb;33(2):149-58. doi: 10.1080/02713680701860499.


Purpose: The aim of this study was to investigate whether the ocular pharmacokinetic parameters observed following systemic administration are also seen following topical administration.

Methods: Azithromycin concentrations were measured by HPLC-MS in pigmented rabbits' tears, cornea, bulbar conjunctiva, and aqueous humor following single instillation and twice-daily instillations for three consecutive days of topical 1.50% azithromycin dihydrate solution.

Results: Following a single administration, azithromycin levels were higher than the MIC 4 microg/g breakpoint for susceptible germs for at least 4 hr in tears, 1 hr in conjunctiva, and 1 hr in cornea after instillation. Following multiple administrations, azithromycin levels were higher than the MIC 4 microg/g for at least 16 hr in tears, 24 hr in conjunctivae, and 1 week in cornea after the last instillation.

Conclusions: Both dosage regimens resulted in adequate and long-lasting azithromycin levels in the conjunctiva, the ocular target tissue relative to the expected therapeutic indication in man (bacterial conjunctivitis), and also in the cornea and tears.

MeSH terms

  • Animals
  • Anti-Bacterial Agents / administration & dosage
  • Anti-Bacterial Agents / pharmacokinetics*
  • Aqueous Humor / metabolism*
  • Azithromycin / administration & dosage
  • Azithromycin / pharmacokinetics*
  • Biological Availability
  • Chromatography, High Pressure Liquid
  • Conjunctiva / metabolism*
  • Cornea / metabolism*
  • Mass Spectrometry
  • Microbial Sensitivity Tests
  • Rabbits
  • Tears / metabolism*
  • Tissue Distribution


  • Anti-Bacterial Agents
  • Azithromycin