Study: Levofloxacin induced least toxicity, apoptosis

Fort Lauderdale, FL-In a study performed to evaluate and compare preserved versus unpreserved fluoroquinolone antibiotics, cell culture assays demonstrated some degree of toxicity and elevated induction of apoptosis in each of three commercially available topical ocular fluoroquinolone antibiotics, according to Seth P. Epstein, MD, who presented a poster on his work with colleagues at the annual meeting of the Association for Research in Vision and Ophthalmology.

Of the three, nonpreserved levofloxacin ophthalmic solution 1.5% (Iquix, Santen/Vistakon Pharmaceuticals) induced the least toxicity and apoptosis, followed closely by nonpreserved moxifloxacin ophthalmic solution 0.5% (Vigamox, Alcon Laboratories), while gatifloxacin ophthalmic solution 0.3% (Zymar, Allergan), which is preserved with 0.005% benzalkonium chloride (BAK), had the greatest levels of both toxicity and apoptosis, said Dr. Epstein, assistant professor of ophthalmology, Mount Sinai School of Medicine, New York, NY.

"There's been a great deal in the literature about the toxicity of BAK," Dr. Epstein said. "Previous work in our lab has determined that of the five classes of preservatives that are in use, BAK is one of the most toxic. It also is one of the most commonly used.

In this study, the investigators evaluated the toxicity and apoptosis induced by the antibiotics using a cell culture model consisting of an MTT (method of transcriptional and translational) cytotoxicity assay and a TUNEL (terminal deoxynucleotidyl transferase dUTP nick end labeling) apoptosis assay. Preconfluent immortalized conjunctival and human corneal epithelial cells were each incubated with the three commercial antibiotic preparations.