Browsing by Author "Basci N.E."

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    Effects of trauma and infection on ciprofloxacin levels in the vitreous cavity
    (Lippincott Williams and Wilkins, 1999) Öztürk F.; Kortunay S.; Kurt E.; Ilker S.S.; Inan U.U.; Basci N.E.; Bozkurt A.; Kayaalp S.O.
    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 μg/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.
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    Ofloxacin levels after intravitreal injection. Effects of trauma and inflammation
    (1999) Öztürk F.; Kortunay S.; Kurt E.; Inan Ü.Ü.; Ilker S.S.; Basci N.E.; Bozkurt A.; Kayaalp S.O.
    Purpose: This study was carried out to get an insight into the ofloxacin elimination after intravitreal injection in rabbits. We also studied the effects of trauma and inflammation on the vitreous ofloxacin levels after intravitreal injection of ofloxacin. Methods: A penetrating eye injury in the right eye was inflicted on 24 rabbits and another 12 animals were used as control. A standardized intraocular inflammation was induced by intravitreal injection of a suspension of Staphylococcus aureus in half of the traumatized eyes. Ofloxacin (200 μg/0.1 ml) was injected into the midvitreous cavity of both traumatized and control right eyes, and samples were obtained at 2, 8, 24 and 48 h after injection. Drug concentrations were measured using high-pressure liquid chromatography analysis. Results: Vitreous levels of ofloxacin were above the MIC90 at 2 and 8 h in all groups for most of the common microorganisms causing endophthalmitis and also at 24 h in traumatized-infected eyes. At the second hour, the mean vitreous concentrations of ofloxacin both in traumatized and traumatized-infected eyes were lower than that in the control eyes (p < 0.05). At 8 h, the mean vitreous concentrations of ofloxacin in the traumatized and in the traumatized-infected eyes were higher than that in the control eyes (p < 0.05). At 24 h, the mean ofloxacin concentration was higher in the traumatized-infected eyes than that in control (p < 0.01) and traumatized eyes (p < 0.05), and also higher in the traumatized eyes than that in the control eyes (p < 0.05). The mean ofloxacin concentrations in the traumatized and traumatized-infected eyes were significantly higher (p < 0.01) than those in the controls at 48 h. The elimination half-life of ofloxacin in the control eyes was 5.65 h and trauma and inflammation prolonged the half-life to 9.47 and 9.72 h, respectively. Conclusion: Clearance of ofloxacin is fast and appears to be reduced by trauma and inflammation. Therapeutic drug levels in traumatized-infected eyes were maintained up to 24 h. This may be an important pharmacokinetic advantage in treating endophthalmitis unless the dose used has local toxicity and allows a longer dose interval when the dose is repeated.
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    Penetration of topical and oral ciprofloxacin into the aqueous and vitreous humor in inflamed eyes
    (Lippincott Williams and Wilkins, 1999) Öztürk F.; Kortunay S.; Kurt E.; Ilker S.S.; Basci N.E.; Bozkurt A.
    Purpose: To assess the aqueous and vitreous penetration of ciprofloxacin after topical and combined topical and oral administration and investigate the effects of inflammation on drug penetration. Methods: A standardized penetrating injury was made in the right eyes of 16 rabbits. Intraocular inflammation was induced by intravitreal injection of a suspension of Staphylococcus aureus in these eyes. The animals were divided into two groups according to treatment methodology: topical and topical-oral. The intact left eyes of the animals were maintained as controls. In the topical treatment group, two drops of ciprofloxacin 0.3% were instilled to both eyes every 30 minutes for 4 hours. In the topical-oral treatment group, animals were given two oral 40 mg/kg doses of ciprofloxacin at 12-hour intervals. After the last oral dose, the protocol of the topical group was applied to these eyes. Half an hour after the last drop, 100-μL samples were taken from aqueous and vitreous humor of all eyes. Drug concentrations were measured using high- pressure liquid chromatography. Results: Mean aqueous levels of ciprofloxacin in control eyes were 2.31 μg/mL (range, 1.02-6.27 μg/mL) in the topical group and 5.88 μg/mL (1.52-17.81) in the topical-oral group. Mean aqueous levels in inflamed eyes were 7.36 μg/mL (2.34-17.15) in the topical group and 14.43 μg/mL (2.18-18.66) in the topical-oral group. Mean vitreous levels in control eyes were 0.77 μg/mL (0.09-1.93) in the topical group and 1.01 μg/mL (0.49-1.57) in the topical-oral group. Mean vitreous levels in inflamed eyes were 0.95 μg/mL (0.18-1.27) in the topical group and 1.98 μg/mL (0.51-3.34) in the topical-oral group. There was no significant difference among the groups (P > 0.05). Mean aqueous levels in all eyes and mean vitreous levels in the combined topical and oral group of inflamed eyes were above the 90% minimum inhibitory concentration for most of the common microorganisms causing endophthalmitis. Conclusion: There is an increase in both aqueous and vitreous humor concentrations with inflammation and with oral and topical administrations, as opposed to topical only, of ciprofloxacin. Using oral as well as topical treatment may be a beneficial method of antibiotic prophylaxis in ocular trauma once a patient has received intravenous or intravitreal therapy.