Ocular toxicity of intravitreal vidarabine solubilized in dimethyl sulfoxide

Intravitreal injections of the antiviral drug vidarabine in doses of 10, 50, 100, and 200 micrograms dissolved in 100% dimethyl sulfoxide (DMSO) were administered to the eyes of 12 Dutch and New Zealand pigmented rabbits to determine ocular toxicity. The eyes were examined one week, one month, and two months after inoculation with slit-lamp biomicroscopy, indirect ophthalmoscopy, electroretinography, and histopathologic examination with light and electron microscopy. No permanent damage to ocular tissue was found at a vidarabine concentration of 100 micrograms/mL. The antiviral activity and the toxicity of the vidarabine dissolved in DMSO were tested in vitro on herpes simplex virus type 1-infected rabbit corneal fibroblast monolayers. Vidarabine dissolved in DMSO was found to possess in vitro antiviral activity against herpes simplex virus type 1. Our results suggest that the intravitreal administration of vidarabine dissolved in DMSO may be a safe and effective means of drug therapy.