Antiviral Activity of Win 41258-3, a Pyrazole Compound, Against Herpes Simplex Virus in Mouse Genital Infection and in Guinea Pig Skin Infection

Win 41258-3 (4-[6-(2-chloro-4-methoxyphenoxy)hexyl]-3,5-diethyl-1H-pyrazole methane sulfonate) has in vitro and in vivo activity against herpes simplex virus types 1 and 2. In cell culture, a concentration of 2 microgram/ml produced a greater than 50% inhibition of plaque formation of herpes simplex virus type 2, and 3 microgram/ml produced a 100% reduction of herpes simplex virus type 1. Win 41258-3 was effective against herpes simplex virus types 1 and 2 in mouse genital infection after intravaginal administration. Win 41258-3 was administered to mice at 4 h postinfection with solutions containing 1.25, 2.5, 5, or 10% of the compound in saturated tampons. Therapy resulted in a high survival rate (80 to 100%) of treated animals versus 20 to 30% of placebo-treated controls. Win 41258-3 was also effective in guinea pig skin infection produced by herpes simplex virus type 1. Solutions of 2.5, 5, and 10% Win 41258-3, applied to the skin starting 24 h postinfection, resulted in rapid suppression of development of herpetic vesicles and significant reduction of the virus titers in the lesion sites.