Cytotoxicity Comparison of the Fourth–Generation Fluoroquinolones Gatifloxacin and Moxifloxacin in Primary Rabbit Corneal Epithelial Cell Layers Using an Ethidium Bromide Staining Assay

Abstract

Abstract: : Purpose: To compare the cytotoxicity upon the rabbit corneal epithelial cell layers (RCECL) of gatifloxacin (Zymar^®) versus moxifloxacin (Vigamox^TM) using an ethidium bromide staining assay Methods: Corneal epithelial cells were harvested from New Zealand White rabbit cornea and cultured on Transwell^TM filters until confluency (Day 5–6) according to an established method. Cytotoxicity assessment of RCECL was conducted with Zymar^® (0.3% gatifloxacin preserved with 0.0005% benzalkonium chloride [BAK], Allergan, Inc.) and Vigamox^TM (0.5% moxifloxacin, unpreserved, Alcon Laboratories, Inc.) by ethidium bromide staining. Fluoroquinolone solutions were applied to the apical compartment (tear side) of the Transwells containing RCECL and cells were incubated at 37^oC for 15 and 30 min. Results:In the 30 min cytotoxicity studies with marketed fluoroquinolones, Vigamox^TM resulted in 3.0 x greater cytotoxicity compared to Zymar^® (p<0.001). Similarly, a 15 min treatment to the apical compartment of RCECL resulted in 2.8 x greater cytotoxicity of Vigamox^TM compared to that of Zymar^® (p<0.001). Conclusions: Despite the presence of BAK, Zymar^® resulted in significantly lower cytotoxicity and cell membrane disruption, as measured by ethidium bromide staining, compared to Vigamox^TM. These results are consistent with recently reported in–vitro and clinical results.

Keywords: antibiotics/antifungals/antiparasitics • cornea: epithelium • drug toxicity/drug effects