Browsing by Author "Başci N.E."

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    The effects of prolonged acute use and inflammation on the ocular penetration of topical ciprofloxacin
    (2000) Öztürk F.; Kurt E.; Inan Ü.Ü.; Kortunay S.; Ilker S.S.; Başci N.E.; Bozkurt A.
    Purpose: To study the aqueous and vitreous penetration of ciprofloxacin after prolonged acute topical administration and to investigate the effects of inflammation on drug penetration. Methods: A standardized model of intraocular infection after penetrating injury was made in the right eyes of eight rabbits. The intact left eyes were maintained as the control. Two drops of ciprofloxacin 0.3% eyedrops were instilled topically every 1 h for 7 h to all eyes of the rabbits. Aqueous and vitreous samples (100 μl) were obtained half an hour after the last drop. Instillation was continued for 7 h more and samples were obtained as before. Drug concentrations were measured using HPLC. Results: The mean aqueous humor levels of ciprofloxacin were: in control eyes 1.31 ± 0.78 μg/ml after 7 h and 1.85 ± 1.69 μg/ml after 14 h of instillation; in inflamed eyes 2.18 ± 1.02 μg/ml after 7 h and 2.91 ± 2.12 μg/ml after 14 h. The mean vitreous humor levels were: in control eyes 0.65 ± 0.44 μg/ml after 7 h and 0.72 ± 0.8 μg/ml after 14 h of instillation; in inflamed eyes 0.67 ± 0.77 μg/ml after 7 h and 1.01 ± 0.43 μg/ml after 14 h. However, the differences among the groups were not significant (P > 0.05). Conclusions: Ciprofloxacin penetration into aqueous humor was higher in 14-h topical application than that for 7 h. Inflammation increased the penetration of topical ciprofloxacin into aqueous while administered for 7 h and into both aqueous and vitreous humor while administered for 14 h. (C) 2000 Elsevier Science B.V.
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    Penetration of topical and oral ofloxacin into the aqueous and vitreous humor of inflamed rabbit eyes
    (2000) Öztürk F.; Kurt E.; Inan Ü.Ü.; Kortunay S.; Ilker S.S.; Başci N.E.; Bozkurt A.
    Purpose: This study aimed to investigate the penetration of topical and oral ofloxacin into aqueous humor and vitreous humor in post-traumatic endophthalmitis model in rabbits. Methods: A standardized intraocular infection after penetrating injury was made in the right eyes of 16 rabbits. Intraocular infection was induced by intravitreal injection of a suspension of Staphylococcus aureus. The intact left eyes were maintained as controls. The animals were divided randomly into two groups. (1) In the topical group, two drops of ofloxacin 0.3% eyedrops were instilled to both eyes every 30 min for 4 h. (2) In the topical-oral group, two doses of 25 mg/kg of ofloxacin at 12-h intervals were given orally, then the protocol of the first group was applied. Aqueous and vitreous humor samples were taken 30 min after the last drop. Ofloxacin concentrations were measured by using HPLC. Results: Mean aqueous levels of ofloxacin in control eyes were: 3.25 ± 2.55 μg/ml in topical group, 4.58 ± 5.39 μg/ml in topical-oral group. Mean aqueous levels in inflamed eyes were: 5.21 ± 4.55 μg/ml in topical group, 10.34 ± 8.88 μg/ml in topical-oral group. Mean vitreous levels of ofloxacin in control eyes were: 0.17 ± 0.07 μg/ml in topical group, 1.30 ± 1.23 μg/ml in topical-oral group. Mean vitreous levels in inflamed eyes were: 0.35 ± 0.22 μg/ml in topical group, 3.48 ± 2.69 μg/ml in topical-oral group. There was no significant difference among the groups (P > 0.05), however. Conclusions: The result of this study suggests that oral supplementation of ofloxacin to topical instillation increased the ocular levels of ofloxacin in the post-traumatic endophthalmitis model. Mean drug concentrations in aqueous and vitreous humors were above the 90% minimum inhibitory concentrations (MIC90) for most of the common microorganisms causing endophthalmitis in all eyes, except in the vitreous humors of the intact eyes instilled topically. (C) 2000 Elsevier Science B.V.