SPL Set ID: 3b6ac164-0f1e-4f36-94a1-1fdb07d710f5

XERESE contains acyclovir, a synthetic nucleoside analogue active against herpes viruses, and hydrocortisone, an anti-inflammatory corticosteroid, combined in a cream for topical administration. Each gram of XERESE contains 50 mg (equivalent to 5%, w/w) of acyclovir, 10 mg (equivalent to 1%, w/w) of hydrocortisone and the following inactive ingredients: cetostearyl alcohol, citric acid monohydrate, isopropyl myristate, mineral oil, Poloxamer 188, propylene glycol, purified water, USP, sodium hydroxide, sodium lauryl sulfate, and white petrolatum. Sodium hydroxide or hydrochloric acid may have been added to adjust the pH to approximately pH 5. Acyclovir, 2-Amino-9-[(2-hydroxyethoxy)methyl]-1,9-dihydro-6H-purin-6-one, is a synthetic nucleoside analogue active against herpes viruses. The maximum solubility of acyclovir in water at 37°C is 2.5 mg/mL. The pKa’s of acyclovir are 2.27 and 9.25. Its empirical formula is C 8 H 11 N 5 O 3 . The structural formula is provided in Figure 1: Figure 1: Structural Formula of Acyclovir Hydrocortisone, pregn-4-ene-3,20-dione, 11,17,21-trihydroxy- (11β), is an anti-inflammatory corticosteroid. Its empirical formula is C 21 H 30 O 5 . The structural formula is provided in Figure 2: Figure 2: Structural Formula of Hydrocortisone Structural Formula of Acyclovir Structural Formula of Hydrocortisone