Studies on intravitreal penetration with penicillin and penicillin therapy of vitreous infections
Leopold, I.H.; Wiley, H.
Arch Ophthalmol 33(3): 211-216
The penetration of penicillin into the vitreous of normal rabbit eyes and rabbit eyes with experimentally inflamed anterior segments was measured following several adm. methods. Intravitreous and intramuscular routes failed to produce detectable levels in the vitreous of normal eyes when 4000 Oxford units of Na penicillin/kg. were used. Although higher levels occurred in the vitreous of the inflamed eyes by these methods they still were not above .08 units/ml. Subconjunctival and anterior chamber injns. of penicillin produced levels above 0.2 units/ml. in the vitreous of normal eyes and even greater concs. in the vitreous of inflamed eyes. The following modes of penicillin adm. were compared for therapeutic effectiveness against a standard vitreous infection: direct intravitreous, subconjunctival, anterior chamber and intravenous injns. The infections were produced by a diluted 18 hr. broth culture of hemolytic Staphylococcus aureus known to be sensitive in serum to .05-.02 Oxford units of penicillin. Intravenous injns. of penicillin failed to stop the progression of the infections. Repeated subconjunctival injns. of penicillin and injns. into the anterior chamber halted the progress of infection in 4 of 10 rabbit eyes. Intravitreal injns. halted the progress of infections in all eyes receiving one injn. consisting of more than 500 Oxford units of penicillin. All forms of therapy were instituted 2 hrs. after inoculating the vitreous with the infecting organism.