PHARMACOKINETICS OF TOPICALLY APPLIED CIPROFLOXACIN IN RABBIT TEARS

Fluoroquinolones provide an important single antibiotic therapy for ba cterial keratitis caused by Staphylococcus aureus and numerous gram-ne gative bacteria, including Pseudomonas aeruginosa. The pharmacokinetic s of three ocular fluoroquinolones, norfloxacin (CHIBROXIN(R), Merck, Sharp & Dohme), ciprofloxacin (CILOXAN(R), Alcon Laboratories), and of loxacin (OCUFLOX(TM), Allergan Pharmaceuticals), have been studied in the human eye and in both the normal rabbit eye and rabbit models of k eratitis. However, the pharmacokinetics of ciprofloxacin have not been previously studied in the tear film of rabbits. This study was done t o determine the pharmacokinetics of topical ciprofloxacin in the rabbi t tear film. Two drops of CILOXAN(R) were applied to the eyes of norma l rabbits. Tear samples were collected at 5, 10 and 30 minutes, and 1, 2, 4 and 6 hours after topical drug application. Tear samples were an alyzed for ciprofloxacin concentrations by HPLC. Ciprofloxacin concent rations reached a peak at 5 minutes, then declined in a manner similar to that reported for norfloxacin and ofloxacin. The ciprofloxacin con centrations in tears were substantially higher throughout the length o f the study than the MIC(90) for most ocular pathogens including Staph ylococcus aureus and Pseudomonas aeruginosa.