Diffusion of pefloxacin in the aqueous humor and crystalline lens after repeated oral administration in man

: The intraocular penetration of pefloxacin was evaluated in 38 patients undergoing extracapsular cataract extraction. Patients were treated for three days with 400 mg of pefloxacin every twelve hours (the first dose being 800 mg). The mean maximum concentration of pefloxacin reached six hours after the last dose in the aqueous humor was 7.69 +/- 3.50 mg/l and reached twelve hours after the last dose in the lens was 4.59 +/- 3.15 micrograms/g. Antibiotic levels were measured by high performance liquid chromatography. Several doses until plasma steady state were effective in obtaining a higher level than a single dose of 400 mg. The ratio between aqueous humor and serum concentrations ranged between 0.50 and 0.89 (mean 68%). These concentrations in aqueous humor were higher than the MIC90 of pefloxacin for most bacterial pathogens involved in endophthalmitis 24 hours after the last dose.