2,4,6,8-Tetraoxa-5-phosphanonanedioic acid, 5-[[2-(6-amino-9H-purin-9-yl)-1-methylethoxy]methyl]-, bis(2-methylpropyl) ester, 5-oxide, (R)- 201340-99-0 AIDS-007932 AIDS007932 Bis(IsobutylOC)PMPA PMPA prodrug Tenofovir prodrug