Abstract
Abstract: :
Purpose: Use of fluoroquinolone agents for bacterial keratitis requires the adequate stromal drug concentrations that exceed the minimal inhibitory concentrations for common corneal pathogens. This study was designed to determine the corneal stromal penetration of topically applied three fluoroquinolones, levofloxacin, norfloxacin, and lomefloxacin, in human tissue obtained from patients undergoing penetrating keratoplasty. Methods: Fourteen patients received three drops of each of 0.5% levofloxacin, 0.3% norfloxacin, and 0.3% lomefloxacin at 15 min intervals, beginning 90 minutes before their scheduled keratoplasty. Corneal samples obtained from the excised buttons at the time of surgery were stored at -80 ° C until analysis. The samples were analyzed for drug concentration using high-performance liquid chromatography. The elution was performed using ODS-80 column with a mobile phase of 85:15 mixture of pH 3.0, 0.05M phosphoric acid and acetonitrile. Flow rate was set at 0.7 mL/min and detection was by fluorescence (excitation 290 nm, emission 470 nm). Results: Intracorneal concentration of levofloxacin was the highest among 3 tested drugs in most cases, although a great degree of interpatient variability was present. A mean corneal tissue concentration of levofloxacin (4.63 ± 3.53 µg/mg ;mean ± standard deviation) was significantly higher than those of lomefloxacin (2.74 ± 1.78 µg/mg) and norfloxacin (1.33 ± 1.18 µg/mg). Conclusion: The mean concentration of levofloxacin in the corneal stroma was higher than those of norfloxacin and lomefloxacin. However, corneal penetration of fluoroquinolones was variable in patients, and in some cases, did not exceed the minimal inhibitory concentrations for some common pathogens.
Keywords: 319 antibiotics/antifungals/antiparasitics • 449 keratitis • 587 Staphylococcus