Intracameral moxifloxacin: In vitro safety on human ocular cells

PURPOSE: The fourth-generation fluoroquinolone, moxifloxacin, covers most gram-positive and gram-negative isolates causing endophthalmitis. It is safe and effective for systemic and topical use, but only limited data are available on prophylactic intracameral administration to prevent endophthalmitis. This study uses a cell culture model to investigate the safety of moxifloxacin for intracameral application. METHODS: Endothelial toxicity of moxifloxacin was evaluated in cultured human corneas. Possible toxic effects of moxifloxacin (10-750 μg/mL) in corneal endothelial cells (CEC), primary human trabecular meshwork cells (TMC), and primary human retinal pigment epithelial (RPE) cells were evaluated after 24 hours and under conditions of oxidative and inflammatory stress by treatment with tumor necrosis factor alpha, lipopolysaccharides, or interleukin-6. Toxicity was evaluated by tetrazolium dye reduction assay, and cell viability was quantified by a microscopic live-dead assay. RESULTS: No corneal endothelial toxicity could be detected after 30 days of treatment with 500 μg/mL moxifloxacin. Concentrations up to 150 μg/mL had no influence on CEC, TMC, or RPE cell proliferation or on cell viability when administered for 24 hours. After preincubation with tumor necrosis factor alpha, lipopolysaccharides, or interleukin-6 for 24 hours and subsequent treatment with moxifloxacin at concentrations from 10 to 150 μg/mL for 24 hours, no significant decrease in proliferation or viability was observed. Hydrogen peroxide exposure did not increase cellular toxicity. CONCLUSIONS: This study showed no significant toxicity for moxifloxacin on CEC, TMC, RPE cells, or human corneal endothelium for concentrations up to 150 μg/mL. The minimum inhibitory concentration of moxifloxacin to inhibit 90% of pathogens commonly encountered in endophthalmitis is known to be in the range of 0.25-2.5 μg/mL. Therefore, prophylactic intracameral use of moxifloxacin at concentrations up to 150 μg/mL may be safely used to prevent endophthalmitis after intraocular surgery.