Intravitreal toxicity of hydroxyacyclovir (BW-B759U), a new antiviral agent.

We investigated the toxicity of the antiviral compound hydroxyacyclovir (9-[hydroxy-1-(hydroxymethyl)ethoxymethyl]guanine, or BW-B759U), following intravitreal injection in the rabbit. Intravitreal doses of 10, 20, 40, 80, 100, 200, and 400 micrograms produced no discernible ophthalmoscopic or histologic changes. Intravitreal doses of 40, 200, and 400 micrograms produced no changes in the electroretinography B-waves. The low level of retinal toxicity and excellent median inhibitory dose values of intravitreal BW-B759U against cytomegalovirus suggest its potential therapeutic utility in the treatment of cytomegalovirus retinitis.