Topotecan Monohydrochloride S Isomer is a potent anticancer drug that belongs to the class of topoisomerase I inhibitors. This drug is widely used in the treatment of ovarian, small cell lung, and cervical cancers. Although there aren't many synonyms for this specific compound, it is often referred to simply as "Topotecan" or "Hycamtin", which is its brand name. Topotecan Monohydrochloride S Isomer works by inhibiting the DNA enzyme topoisomerase I, preventing the replication and repair of cancerous cells. It is available in various forms, including oral capsules and intravenous formulations. This drug has shown promising results in improving patient outcomes and has become an important component in cancer treatment protocols.