Effect of gatifloxacin 0.3% and moxifloxacin 0.5% ophthalmic solutions on human corneal epithelium following 2 dosing regimens

Purpose: To determine whether gatifloxacin 0.3% ophthalmic solution or moxifloxacin 0.5% ophthalmic solutions are toxic to the corneal epithelium when used with 1 of 2 dosing regimens in healthy human eyes. Setting: Price Vision Group, Indianapolis, Indiana, USA. Methods: In this double-masked randomized fellow-eye comparison study, gatifloxacin 0.3% was instilled in 1 eye and moxifloxacin 0.5% in the other eye either 4 times a day for 7 days or hourly for 10 hours. Before and after dosing, all eyes were examined with a slitlamp and the cell layers in the central cornea were evaluated by confocal microscopy. Subject discomfort with study drop instillation was also assessed. Results: There was no statistically significant increase in the incidence or severity of superficial punctuate keratitis following use of gatifloxacin 0.3% or moxifloxacin 0.5% when instilled 4 times a day for 7 days or hourly for 10 hours. Hourly use of gatifloxacin 0.3% for 10 hours resulted in a mild but statistically significant increase in conjunctival hyperemia (P=.029). Use of moxifloxacin 0.5% resulted in a small but statistically significant deterioration of the corneal epithelial surface as assessed by confocal microscopy (P=.045). The incidence of subject discomfort with study drop instillation was comparable for the 2 antibiotics (P=.67). Conclusion: Use of ophthalmic solutions of gatifloxacin 0.3% or moxifloxacin 0.5% did not result in clinically significant epithelial toxicity in healthy human corneas after dosing regimens of 4 times a day for 7 days or hourly for 10 hours dosing regimens.