Evaluation of intraocular penetration of levofloxacin after administration drop solution by high performance liquid chromatography and comparison with ciprofloxacin

Introduction: Levofloxacin is used to treat a wide variety of bacterial infections. Levofloxacin belongs to a class of drugs called quinolone antibiotics. It works by stopping the growth of bacteria.

Fluoroquinolones are suitable for the treatment of ocular infections because of their excellent bactericidal activities and ocular penetration. Among different types of chromatographic methods, HPLC is found to be more effective to achieve separation, identification, purification and quantification of various compounds. Due to favorable pharmacodynamic and pharmacokinetic properties of levofloxacin, this study was evaluated the penetration of levofloxacin after administration of drop solutions. Intraocular penetration of levofloxacin was compared with ciprofloxacin. In this project, we studied the aqueous penetration of levofloxacin, in patients undergoing cataract surgery.

Methods: 33 volunteer patients received one drop of levofloxacin every six hours over three days before cataract surgery and on the day of surgery administration of drug was stopped one hour before surgery. Aliquot of Aqueous samples were stored at -20 ̊ C. The samples were thawed, mixed for one minute and centrifuged for 10 minute at 3000 g and 20 μl of the clear supernatant injected into the column of HPLC analysis to assay by reversed-phase HPLC method. The mobile phase consisted of a mixture of acetonitrile and aqueous solution. Levofloxacin concentration was evaluated by HPLC method with fluorescence detector. Peak area was selected as the best parameter for plotting calibration curves by an integration pack program.

Results: A simple, effective and sensitive HPLC assay for determination of levofloxacin in human ocular aqueous was validated. Linearity was shown for levofloxacin concentration over a wide range of 1.95×10-3-1.50 μg/ml. The average level of the levofloxacin in the ocular aqueous was found to be higher than the MIC values that have been reported in the literature for a common bacterium. On the other hand, penetration of levofloxacin into aqueous humor in the patients who received eye drops of levefloxacin is much better than patients who received eye drops of ciprofloxacin. The result of experiments shows that, levofloxacin is a favorable antibiotic because of its ability to penetrate the surgical site with effective concentration.

Conclusions: Levofloxacin concentration was measured by HPLC proposed method that found to be less expensive, simple, rapid and sensitive. The results of experiments reveal that administration of levofloxacin as an eye drop can be more effective than ciprofloxacin because of its high concentration detected in human ocular aqueous rather than ciprofloxacin. In conclusion, this protocol is applicable for drug monitoring in patients undergoing prophylactic antibiotic therapy prior to surgery.