Penetration of topically applied ciprofloxacin, norfloxacin, and ofloxacin into the aqueous humor.

Abstract

To determine the intraocular penetration of topically applied fluoroquinolone antibiotics into aqueous humor. Thirty-two patients undergoing cataract extraction received either 0.3% ciprofloxacin, 0.3% norfloxacin, or 0.3% ofloxacin topical drops. The patients were given two drops 90 minutes preoperatively and two drops 30 minutes preoperatively. At the time of surgery, 0.1 ml aqueous fluid was aspirated from the anterior chamber and immediately stored at -70 degrees C. Concentrations of ciprofloxacin, norfloxacin, and ofloxacin were determined using a broth dilution bioassay. Morganella morganii with a known minimal inhibitory concentration was used to assay ciprofloxacin and norfloxacin levels. Salmonella enteritidis with a known minimal inhibitory concentration was used to assay ofloxacin levels. Topically applied ciprofloxacin achieved a mean aqueous level of 0.072 microgram/ml (range, 0.02-0.153 microgram/ml). One sample was below the sensitivity of the bioassay. Topical norfloxacin achieved a mean aqueous level of 0.0570 microgram/ml (range, 0.046-0.10 microgram/ml). Seven samples did not reach the sensitivity of the bioassay. Topical ofloxacin achieved a mean level in the aqueous humor of 0.338 microgram/ml (range, 0.078-0.625 microgram/ml). There was no statistically significant difference in intraocular aqueous humor levels of ciprofloxacin versus norfloxacin (P > 0.05). Topical ofloxacin achieved aqueous humor levels significantly higher than either ciprofloxacin or norfloxacin (P < 0.004). Of the currently available topical fluoroquinolone antibiotics, ofloxacin achieves the highest aqueous humor concentrations.