TOPICAL 0-CENTER-DOT 3-PERCENT CIPROFLOXACIN, NORFLOXACIN, AND OFLOXACIN IN TREATMENT OF BACTERIAL KERATITIS - A NEW METHOD FOR COMPARATIVE-EVALUATION OF OCULAR DRUG PENETRATION

Aims-This study was designed to assess the relative corneal penetratio n of topical drops of three antibiotics and to relate those levels to minimum inhibitory concentrations for organisms associated with bacter ial keratitis. Methods-Four drops of each of ciprofloxacin, norfloxaci n, and ofloxacin (0.3% topical ophthalmic preparations) were given to 12 patients undergoing corneal transplantation. After the recipient ti ssue was removed, corneal drug penetration was measured using high per formance liquid chromatography. Results-Intracorneal concentrations of ofloxacin (geometric mean 0.81 mg kg-l) were significantly higher tha n both ciprofloxacin (0.60 mg kg(-1); p=0.048) and norfloxacin (0.54 m g kg(-1); p=0.012). Ciprofloxacin and norfloxacin concentrations did n ot differ significantly (p=0.33). Conclusions-Review of the minimum in hibitory concentrations of the fluoroquinolones against ocular pathoge ns reveals that ciprofloxacin is more potent than ofloxacin against ma ny bacteria; ofloxacin is in turn more potent than norfloxacin. These data favour the selection of ciprofloxacin and ofloxacin rather than n orfloxacin for the empirical treatment of corneal infection. The great er potency of ciprofloxacin offsets the superior penetration of ofloxa cin. There is a need for improved clinical trial data concerning the u se of fluoroquinolone eyedrops in ulcerative keratitis; some encouragi ng data are available for ciprofloxacin but not (in humans) for norflo xacin or ofloxacin.