DENAVIR (penciclovir) cream 1% contains penciclovir, an antiviral agent active against herpes viruses. DENAVIR is available for topical administration as a 1% white cream. Each gram of DENAVIR contains 10 mg of penciclovir and the following inactive ingredients: cetostearyl alcohol, mineral oil, polyoxyl 20 cetostearyl ether, propylene glycol, purified water and white petrolatum. Chemically, penciclovir is known as 9-[4-hydroxy-3-(hydroxymethyl)butyl] guanine. Its molecular formula is C10H15N5O3; its molecular weight is 253.26. It is a synthetic acyclic guanine derivative and has the following structure:

Penciclovir is a white to pale yellow solid. At 20°C it has a solubility of 0.2 mg/mL in methanol, 1.3 mg/mL in propylene glycol, and 1.7 mg/mL in water. In aqueous buffer (pH 2) the solubility is 10.0 mg/mL. Penciclovir is not hygroscopic. Its partition coefficient in n-octanol/water at pH 7.5 is 0.024 (logP = -1.62).^[1]

Adapted from the FDA Package Insert.