[Experimental studies of 9-(1, 3-dihydroxy-2-propoxymethyl)-guanine(DHPG) against herpes simplex virus]

The antiherpes virus effects of 9-(1,3-dihydroxy-2-propoxymethyl) guanine (DHPG) were studied in cell culture and in experimental herpetic keratitis in rabbits. In plaque reduction assays in Vero cell, the 50% inhibitory concentration (IC50) of DHPG was shown to be 0.1 microgram/ml against HSV-1. Combination of DHPG and Cyclocytidine (CC), produced a synergistic activity against kos strains of HSV-1. Whereas the combination of DHPG and Acyclovir (ACV) or Tai-Ding-An (TDA) resulted in an additive interaction against HSV-1. Topical application of 0.1% or 0.05% DHPG eyedrop was initiated 48h after virus inoculation, significant efficacy was obtained in rabbits with herpetic epithelial keratitis. But 0.025 and 0.01% DHPG eyedrop showed no effect. 0.1% DHPG has been shown to be effective in the topical treatment of herpetic stromal keratitis in the rabbits.