6H-Purin-6-one, 2-amino-1,9-dihydro-9-(4-hydroxy-3-(hydroxymethyl)butyl)- & 2-Amino-1,9-dihydro-9-[(2-hydroxyethoxy)methyl]-6H-purin-6-one AIDS-093108 AIDS093108 Penciclovir & Aciclovir