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.


CONCLUSIONS
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.
Oztürk
F
F
Department of Ophthalmology, Faculty of Medicine, Celal Bayar University, Manisa, Turkey.
Kortunay
S
S
Kurt
E
E
Ilker
S S
SS
Inan
U U
UU
Basci
N E
NE
Bozkurt
A
A
Kayaalp
O
O
D000818:Animals; D000890:Anti-Infective Agents / Q000008:administration & dosage / Q000493:pharmacokinetics*; D002851:Chromatography, High Pressure Liquid; D002939:Ciprofloxacin / Q000008:administration & dosage / Q000493:pharmacokinetics*; D015818:Eye Infections, Bacterial / Q000378:metabolism* / Q000382:microbiology; D015807:Eye Injuries, Penetrating / Q000378:metabolism* / Q000382:microbiology; D006207:Half-Life; D007267:Injections; D011817:Rabbits; D013203:Staphylococcal Infections / Q000378:metabolism* / Q000382:microbiology; D013211:Staphylococcus aureus / Q000472:pathogenicity; D014822:Vitreous Body / Q000378:metabolism* / Q000382:microbiology
D000890:Anti-Infective Agents; D002939:Ciprofloxacin