9-((2R,4S,5R)-4-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-1H-purin-6(9H)-one-13C5;1,9-Dihydro-9-(2’-deoxy-?-D-ribofuranosyl)-6H-purin-6-one-13C5; 9-(2-Deoxy-?-D-erythro-pentofuranosyl)-1,9-dihydro-6H-purin-6-one-13C5; Hypoxanthine Deoxyriboside-13C5; Didanosine-13C5 EP Impurity C;2'-Deoxyinosine-13C5
