Intraocular ciprofloxacin levels after oral administration in silicone oil-filled eyes.

PURPOSE. To evaluate penetration of oral ciprofloxacin in the retro-silicone oil space fluid (RSOF) in silicone oil (SO)-filled eyes. METHODS. One dose of 750 mg ciprofloxacin was given to two groups of five patients with vitrectomized eyes with SO endotamponade, 4 hours (group D and 8 hours (group II) before SO removal. In 10 vitrectomized eyes with SO endotamponade (group III) and another 10 patients scheduled for vitrectomy for the first time (group TV), two 750-mg doses every 12 hours, with the last dose 12 hours before surgery, were given. Blood samples were taken at the time of collection of RSOF samples in groups I, II, and III and of the vitreous in group IV. All samples were assayed for ciprofloxacin by high-performance liquid chromatography. RESULTS. The mean drug concentration in the RSOF was 0.34 ± 0.09, 0.37 ± 0.04, 0.84 ± 0.29, and 0.44 ± 0.11 μg/mL in groups I, II, III, and IV respectively. The mean serum concentration was 1.29 ± 0.63, 1.08 ± 0.14, 1.93 ± 0.84, and 1.34 ± 0.55 μg/mL in groups I, II, III, and IV respectively with no statistically significant difference between groups III and IV (P = 0.081). CONCLUSIONS. Antibiotic levels in the RSOF in SO-filled eyes after oral administration of ciprofloxacin in two 750-mg doses exceeded the minimal inhibitory concentration for 90% of isolates (MIC 90 ) for most bacterial species and was higher than levels reached in the vitreous in nonvitrectomized eyes (P = 0.001).