In vitro and in vivo studies with sodium hyaluronate as a carrier for intraocular gentamicin.

We compared the in vitro growth of common intraocular pathogens Staphylococcus aureus, Staphylococcus epidermidis and Pseudomonas aeruginosa in rabbit vitreous and in sodium hyaluronate (SH) with and without gentamicin. The minimal inhibitory concentration for gentamicin/SH was 0.5, 0.062 and 2.0 mcg/ml for these pathogens, respectively. After posterior capsulotomy, P. aeruginosa was inoculated into the anterior vitreous and all 15 untreated eyes developed endophthalmitis. In a similar group, aqueous gentamicin administered in the anterior chamber reduced the incidence of endophthalmitis to 10 of 15 eyes. Under similar circumstances, the SH/gentamicin combination lowered the incidence of endophthalmitis significantly to 4 of 15 eyes. The half-life of aqueous gentamicin was 0.9 h, which was shorter than the 2.2 h for SH/gentamicin combination. These results suggest that SH may be a useful carrier for intraocular drug therapy.