Ciprofloxacin iontophoresis for aminoglycoside-resistant pseudomonal keratitis

Studies using ciprofloxacin for the therapy of experimental aminoglycoside-resistant keratitis caused by Pseudomonas aeruginosa were conducted using transcorneal iontophoresis as the drug-delivery system. Corneas infected with P. aeruginosa ATCC 27853/pMG6 were treated 22 hours postinfection with ciprofloxacin delivered by iontophoresis (0.8 mA X 10 min), mock iontophoresis (eyecup with no current), or frequently applied topical drops. Iontophoresis of 10 mg/ml or 25 mg/ml of ciprofloxacin significantly reduced the number of viable bacteria per cornea by more than 5 log units compared with untreated controls (P less than 0.0001). Five hours after the initiation of treatment, mock iontophoresis (10 mg/ml or 25 mg/ml) or 11 applications of topical ciproflaxicin drops (7.5 mg/ml) decreased the viable bacteria relative to the untreated controls by 5 log units (P less than 0.0001). One treatment with an eyecup was as effective as 11 treatments with topical drops (P greater than 0.75). One hour after treatment with iontophoresis or mock iontophoresis of 10 mg/ml of ciprofloxacin, aqueous humor concentrations were 83.75 +/- 8.85 micrograms/ml and 24.87 +/- 4.0 micrograms/ml (mean +/- standard error of the mean), respectively. One hour after the last of five applications of 7.5 mg/ml of ciprofloxacin (every 15 min for 1 hr) the aqueous humor concentration was 4.2 +/- 1.14 micrograms/ml. These results show the value of ciprofloxacin in treating aminoglycoside-resistant infections caused by P. aeruginosa and suggest that ciprofloxacin can be efficiently delivered by iontophoresis.