2,2′-(Methylenediazanediyl)bis[9-[(2-hydroxyethoxy)methyl]-1,9-dihydro-6H-purin-6-one]; Bis({9-[(2-hydroxyethoxy)methyl]guanine}-N2-yl)methane; Bis-Acyclovir (USP) ; Valaciclovir EP Impurity L ; Acyclovir N-Methylene Dimer; Valaciclovir Hydrochloride Impurity L (EP/BP); 2,2'-(Methylenebis(azanediyl))bis(9-((2-hydroxyethoxy)methyl)-1,9-dihydro-6H-purin-6-one)