In vitro safety of intravitreal moxifloxacin for endophthalmitis treatment.

PURPOSE

To investigate the safety of moxifloxacin for intravitreal application in a cell culture model.

SETTING

Department of Ophthalmology, Ludwig-Maximilians-Universität, Munich, Germany.

METHODS

Primary human retinal pigment epithelium (RPE) cells, ARPE19 cells, and primary optic nerve head astrocyte (ONHA) cells were treated with concentrations of moxifloxacin ranging from 10 to 750 microg/mL. Possible toxic effects and median inhibitory concentration were evaluated after 24 hours as well as under conditions of oxidative stress. After treating the RPE and ONHA cell lines with tumor necrosis factor-alpha (TNF-alpha; 10 microg/mL), lipopolysaccharides (LPS; 20 microg/mL), and interleukin-6 (IL-6; 20 microg/mL), the effects of moxifloxacin on cellular viability under conditions of inflammation were investigated. Toxicity was evaluated by measuring the inhibition of RPE cell proliferation with the tetrazolium dye-reduction assay (MTT; 3-[4,5-dimethylthiazol- 2-yl]-2,5-diphenyl tetrazolium bromide). Cell viability was quantified by a microscopic live/dead assay.

RESULTS

At concentrations higher than 150 microg/mL, moxifloxacin had adverse effects on primary RPE, ARPE19, and ONHA cell proliferation and viability. Lower concentrations did not affect RPE or ONHA cell proliferation and viability when administered for 24 hours. No significant decrease in proliferation and viability was observed after preincubation with TNF-alpha, LPS, and IL-6 for 24 hours and subsequent treatment with moxifloxacin concentrations of 10 to 150 microg/mL for 24 hours. Hydrogen peroxide exposure did not increase cellular toxicity.

CONCLUSIONS

No significant toxicity of moxifloxacin was seen on primary RPE cells, ARPE19 cells, or ONHA cells at concentrations up to 150 microg/mL. Intravitreal use of moxifloxacin up to this concentration may be safe and effective for the treatment of endophthalmitis.