Excretion of gentamicin in rabbit tears after subconjunctival injection.

We subconjunctivally, injected gentamicin, in a dose of 10 mg, into normal and inflamed (Staphylococcus aureus endophthalmitis) rabbit eyes in which the nasolarcrimal ducts had been blocked. We retrieved approximately 10% of the dose of drug in the tears, the majority in the first 30 minutes. The difference in lacrimal excretion of the drug between normal and inflamed eyes was not significant. Higher concentrations of gentamicin found in the ocular tissues of normal eyes than inflamed eyes cannot be attributed to loss in the tears.