Penetration of tobramycin sulfate in the aqueous humor of the rabbit.

The intraocular penetration of tobramycin sulfate, a new aminoglycoside antibiotic, was evaluated in rabbits following subconjunctival injection. The mean tobramycin sulfate concentration in the aqueous humor 60 minutes after a single 5-mg dose was 5.5 mug/ml, as compared to a mean concentration of 6.7 mug/ml following a single 10-mg dose. These levels exceed the minimal inhibitory concentration (MIC) for most Pseudomonas species and a variety of other Gram-negative bacilli recovered from clinical infection. No anterior segment changes that may be attributed to the antibiotic could be demonstrated in the injected eye.