Ocular pharmacokinetics of AzaSite Xtra-2% azithromycin formulated in a DuraSite delivery system.
OBJECTIVE
The pharmacokinetics of a 2% ocular solution of azithromycin in DuraSite was evaluated in rabbits to determine whether the PK/PD parameters support a once-a-day for three-day therapeutic regimen against bacterial conjunctivitis.


METHODS
Mean levels of azithromycin were determined in tears, bulbar conjunctiva, cornea, and plasma following a single drop of 2% azithromycin. The levels were determined by HPLC-MS.


RESULTS
Concentrations of azithromycin peaked at 30 minutes. At the end of 24 hours, ocular tissue concentrations exceeded the MIC breakpoint for the most common causative pathogens of bacterial conjunctivitis by at least 7-fold.


CONCLUSIONS
The PK/PD profile of 2% azithromycin suggests efficacy against common causative bacteria with just one dose per day for three days.
Si
Erwin C
EC
Department of Preclinical Research, InSite Vision, Alameda, California, USA.
Cheung
Paul S
PS
Bowman
Lyle
L
Hosseini
Kamran
K
D000818:Animals; D000900:Anti-Bacterial Agents / Q000008:administration & dosage / Q000493:pharmacokinetics*; D017963:Azithromycin / Q000008:administration & dosage / Q000493:pharmacokinetics*; D001682:Biological Availability; D002851:Chromatography, High Pressure Liquid; D003234:Conjunctivitis, Bacterial / Q000188:drug therapy; D016503:Drug Delivery Systems; D008297:Male; D008826:Microbial Sensitivity Tests; D011817:Rabbits; D053719:Tandem Mass Spectrometry
D000900:Anti-Bacterial Agents; D017963:Azithromycin