SPL Set ID: 149f4418-7668-4d34-a6f9-69bf3a9c5049

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 USP in a polyethylene glycol (PEG) base. Acyclovir USP is a white to off-white, crystalline powder with the molecular formula C 8 H 11 N 5 O 3 and a molecular weight of 225.2 g/mol. 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 USP is 2-amino-1, 9-dihydro-9- [(2-hydroxyethoxy)methyl]-6 H- purin-6-one; it has the following structural formula: structure.jpg