Collagen shields and intraocular drug delivery: concentration of gentamicin in the aqueous and vitreous of a rabbit eye after lensectomy and vitrectomy.

Five albino New Zealand rabbits underwent bilateral lensectomy and vitrectomy. All left eyes were fitted with a collagen shield that had been soaked for 5 min in 2.0 mL of gentamicin solution (40 mg/mL for IV use). Right eyes were treated with fortified gentamicin drops (13.6 mg/mL) every 30 min for 12 hrs. Aqueous and vitreous specimens were obtained at the following time intervals: 1, 2, 4, 8, 12 and 24 hrs. We found the gentamicin concentrations to be higher in the aqueous of all eyes treated with fortified gentamicin drops. Only those eyes treated with fortified gentamicin drops attained a therapeutic drug level (4 micrograms-9 micrograms/mL) in the aqueous. Therapeutic drug levels were not attained in the vitreous of either treatment group.

Intravitreal recombinant tissue plasminogen activator in the treatment of experimentally induced bacterial endophthalmitis.

Intravitreal injection of antibiotics has been shown to be effective in the treatment of bacterial endophthalmitis, but does not prevent the formation of fibrin. Recombinant tissue plasminogen activator (rTPA), a fibrinolytic agent, was evaluated in experimentally induced Staphylococcus aureus endophthalmitis in an animal model. Significant fibrinous reaction in the vitreous was present in three of six eyes treated with intravitreal injection of clindamycin and rTPA (50%) and in one of five eyes treated with clindamycin only (20%). Fibrin clot formation in the anterior chamber was present in two of six eyes treated with clindamycin and rTPA (33%) and not observed in the clindamycin treated eyes (0%). These findings suggest that rTPA does not play a beneficial role in the treatment of bacterial endophthalmitis in the presence of the vitreous.