2,4,6,8-Tetraoxa-5-phosphanonanedioic acid, 5-[[2-(6-amino-9H-purin-9-yl)-1-methylethoxy]methyl]-, diethyl ester, 5-oxide, (R)- 201340-95-6 AIDS-015622 AIDS015622 Bis(EthylOC)PMPA PMPA prodrug Tenofovir prodrug