SPL Set ID: 9118bbe9-8231-40c8-b11a-6c4a5f41aa16

Penciclovir cream, 1% contains penciclovir, an antiviral agent active against herpes viruses. Penciclovir cream, 1% is available for topical administration as a 1% white to off-white homogenous cream. Each gram of penciclovir cream, 1% 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 C 10 H 15 N 5 O 3 ; its molecular weight is 253.26. It is a synthetic acyclic guanine derivative and has the following structure: Figure 1: Structural Formula of Penciclovir Penciclovir is a white or off-white crystalline powder. At 20°C it has a solubility of 0.25 mg/mL in methanol, 1.67 mg/mL in propylene glycol, and 1.25 mg/mL in water. In aqueous buffer (pH 2) the solubility is 6.04 mg/mL. Penciclovir is not hygroscopic. Its partition coefficient in n-octanol/water is 0.03. Structural Formula