AQUEOUS AND VITREOUS PENETRATION OF CIPROFLOXACIN FOLLOWING DIFFERENTMODES OF SYSTEMIC ADMINISTRATION

The overall importance of the peak or the mean serum concentrations as predictors of ocular drug penetration is unknown. To address this fun damental question with an agent which shows promise as adjunctive ther apy in the treatment of endophthalmitis, we studied the penetration of ciprofloxacin into the aqueous and vitreous humors following three di fferent modes of systemic administration. New Zealand white rabbits re ceived either a single bolus dose (40 mg kg(-1)), three intermittent d oses of 13.33 mg kg(-1) evenly spaced over an 8 hr period, or a contin uous infusion of 40 mg kg(-1) over an 8 hr period. Pharmacokinetic ana lysis was performed using RSTRIP II, a non-linear, least square regres sion model analysis program. The serum area under the concentration-ti me curve (AUC) values for each mode of drug administration were simila r: 32.9 mu g hr ml(-1) for single dose, 31.9 mu g hr ml(-1) for interm ittent dose, and 33.8 mu g hr ml(-1) for continuous infusion modes. Th e percentage penetration into the aqueous and vitreous were also simil ar; 30.5% and 6.5% for a single dose, 31.6% and 7.4% for intermittent doses and 30.0% and 7.5% for continuous infusion. The penetration into the aqueous and vitreous humors was not influenced by mode of adminis tration. As with other quinolones we have studied, elimination rates w ere similar for the central and peripheral compartments in the post-di stributive phase. Vitreous humor ciprofloxacin concentrations achieved were below that which inhibits most Staphylococcus epidermidis, the m ost common isolate in patients with post-operative endophthalmitis.