SPL Set ID: d04c696f-c072-46f7-9a92-9cbb476c827b

Acyclovir is a synthetic nucleoside analogue active against herpes viruses. Acyclovir Ointment USP, 5% is a formulation for topical administration. Each gram of Acyclovir Ointment USP, 5% contains 50 mg of acyclovir in a polyethylene glycol (PEG) base. Acyclovir is a white, crystalline powder with the molecular formula C 8 H 11 N 5 O 3 and a molecular weight of 225. The maximum solubility in water at 37°C is 2.5 mg/mL. The pka's of acyclovir are 2.27 and 9.25. The chemical name of acyclovir is 2-amino-1,9-dihydro-9-[(2-hydroxyethoxy)methyl]-6 H -purin-6-one; it has the following structural formula: