Effects of trauma and infection on ciprofloxacin levels in the vitreous cavity.

OBJECTIVE: This study was designed to determine the effects of trauma and infection on vitreous ciprofloxacin levels after intravitreal injection of ciprofloxacin in rabbits. METHODS: A penetrating injury was made in the right eyes of 24 rabbits. In the eyes of half of the traumatized animals, a standardized intraocular infection was induced by intravitreal injection of a suspension of Staphylococcus aureus. The intact left eyes of the traumatized group were maintained as controls. Ciprofloxacin (200 microg/0.1 mL) was injected into the midvitreous cavity of both eyes in all animals and samples were obtained at 2, 8, 24, and 48 hours after injection. Drug concentrations were measured using high-pressure liquid chromatography analysis. RESULTS: At the second hour, the mean vitreous concentration of ciprofloxacin in the traumatized eyes was lower than that in control eyes (P<0.05). The mean ciprofloxacin concentrations were significantly higher (P<0.05) in the traumatized-infected eyes than were those in control or traumatized eyes at 24 and 48 hours. The elimination half-life of ciprofloxacin in control and traumatized eyes was 6.02 hours and 5.02 hours, respectively, and infection prolonged the half-life to 15.06 hours. Vitreous levels of ciprofloxacin were above the minimum inhibitory concentration (MIC90) for most of the common microorganisms causing endophthalmitis in all groups at 2 and 8 hours, but also at 24 and 48 hours in traumatized-infected eyes. CONCLUSION: Infection appears to decrease the clearance of ciprofloxacin. Therapeutic drug levels in traumatized-infected eyes were maintained up to 48 hours. Assuming that the animal model used may have a predictive value for the drug elimination in traumatized-infected human eyes, we suggest that local administration of ciprofloxacin every 2 days may be relevant from the therapeutic perspective.

The penetration of ofloxacin into human aqueous humor given by various routes.

This study was designed to measure the concentration of ofloxacin in aqueous humor after topical, oral and intravenous administration in 50 patients undergoing cataract extraction. In Group 1, ofloxacin 0.3% eyedrops were topically instilled ten times and the aqueous humor concentration was 2.73 +/- 0.88 microg/ml. In Group 2, ofloxacin 0.3% eyedrops were topically instilled six times and the aqueous humor concentration was 0.84 +/- 0.61 microg/ml. Aqueous humor concentration 12 hours after 200 mg oral dose in Group 3, was 0.38 +/- 0.12 microg/ml. In Group 4, patients were given ofloxacin as a single intravenous 200 mg dose and the aqueous humor concentration 2 hours after the end of infusion was 0.45 +/- 0.11 microg/ml. Concentrations were determined by high performance liquid chromatography (HPLC) with fluorescence detection. There was a significant difference between Group 1 and the other groups, but not between Group 2 and Groups 3, 4. It was concluded that ofloxacin penetrates the corneal and the blood-aqueous barriers and can achieve good aqueous levels when given topically and systematically. Ofloxacin can be applied topically for external bacterial infections such as conjunctivitis and keratitis. Systematically administered ofloxacin reached higher levels than the MIC for some bacteria which cause endophthalmitis.