Aqueous penetration of moxifloxacin 0.5% ophthalmic solution and besifloxacin 0.6% ophthalmic suspension in cataract surgery patients

Purpose: To determine the aqueous humor concentrations of moxifloxacin and besifloxacin after routine preoperative topical dosing in patients having cataract surgery. Setting: Wilmer Eye Institute, Johns Hopkins University, Baltimore, Maryland, USA. Methods: In this prospective randomized parallel double-masked clinical trial, 1 drop of commercially available moxifloxacin 0.5% ophthalmic solution or besifloxacin 0.6% ophthalmic suspension was administered every 10 minutes for a total of 4 doses beginning 1 hour before routine cataract surgery. Aqueous humor was sampled via the paracentesis, and antibiotic concentrations were determined using validated high-performance liquid chromatography procedures. Results: The study enrolled 50 patients. The aqueous concentration of the antibiotic agent was detectable in all 23 moxifloxacin samples and in 10 (40%) of the 25 besifloxacin samples (P<.0001, Pearson chi-square test). The mean aqueous concentration in the moxifloxacin samples was 50-fold higher than in the besifloxacin samples (1.6108 μg/mL versus 0.0319 μg/mL) when all samples were included (P<.0001, Wilcoxon test), while the moxifloxacin concentration was 38-fold higher than the besifloxacin concentration (1.6108 μg/mL versus 0.0422 μg/mL) in the samples with detectable antibiotic agent (P<.0001). Conclusions: After topical preoperative administration, moxifloxacin 0.5% ophthalmic solution had a 38-fold to 50-fold higher concentration in the aqueous humor than besifloxacin 0.6% ophthalmic suspension. Besifloxacin was undetectable in more than half the aqueous humor samples. Financial Disclosure: No author has a financial or proprietary interest in any material or method mentioned.