Topotecan hydrochloride Topotecan hydrochloride Synonyms: (S)-10-[(Dimethylamino)methyl]-4-ethyl-4,9-dihydroxy-1H-pyrano[3',4':6,7]indolizino[1,2-b]quinoline-3,14(4H,12H)-dione monohydrochloride; Nogitecan hydrochloride; Hycamtin; Topotecan HCl CAS NO.: 119413-54-6 Formula: C23H23N3O5.HCl Weight: 457.90676