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 offloxacin 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 mu g/ml in topical group, 4.58 +/- 5.39 mu g/ml in topical-oral group. Mean aqueous levels in inflamed eyes were: 5.21 +/- 4.55 mu g/ml in topical group, 10.34 +/- 8.88 mu g/ml in topical-oral group. Mean vitreous levels of ofloxacin in control eyes were: 0.17 +/- 0.07 mu g/ml in topical group, 1.30 +/- 1.23 mu g/ml in topical-oral group. Mean vitreous levels in inflamed eyes were: 0.35 +/- 0.22 mu g/ml in topical group, 3.48 +/- 2.69 mu g/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. All rights reserved.