Oral Topotecan Hydrochloride

**Semantic type:** Organic Chemical|Pharmacologic Substance

**Definition:** An oral formulation of the hydrochloride salt of topotecan, a semisynthetic derivative of the quinoline alkaloid camptothecin, with potential antineoplastic activity. Topotecan selectively inhibits topoisomerase I activity by stabilizing topoisomerase I-DNA covalent complexes during the S phase of the cell cycle, thereby inhibiting religation of topoisomerase I-mediated single-strand DNA breaks and producing potentially lethal double-strand DNA breaks when encountered by the DNA replication machinery.

**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 - Oral Hycamtin