Differential aqueous and vitreous concentrations of moxifloxacin and ofloxacin after topical administration one hour before vitrectomy

PURPOSE: To investigate the penetration of ofloxacin and moxifloxacin into the aqueous and vitreous after topical administration one hour before vitrectomy surgery. DESIGN: Prospective, randomized, double,blind case series study. METHODS: Twenty-seven patients undergoing vitrectomy were randomized to receive either topical ofloxacin 0.3% or moxifloxacin 0.5% every 10 minutes for one hour before surgery. Aqueous and vitreous samples were obtained and analyzed using high-performance liquidation chromatography. RESULTS: The moxifloxacin aqueous (1.576 +/- 0.745 mu g/ml) and vitreous (0.225 +/- 0.013 mu g/ml) levels were significantly higher than the ofloxacin aqueous (0.816 +/- 0.504 mu g/ml) (P =.0009) and vitreous (0.225 +/- 0.013 mu g/ml) [P=.0054] levels, respectively. The mean moxifloxacin aqueous and vitreous levels exceeded the minimum inhibitory concentration for 90% of isolates (MIC90) for a wide variety of bacteria implicated in endophthalmitis. In contrast, the aqueous level of ofloxacin exceeded the MIC90 of only a few organisms. CONCLUSIONS: Moxifloxacin applied every 10 minutes during the hour before vitrectomy penetrated the eye significantly better than ofloxacin.