Topotecan Sustained-release Episcleral Plaque

**Semantic type:** Pharmacologic Substance

**Definition:** An episcleral plaque containing sustained-release (SR) topotecan, a semisynthetic derivative of camptothecin and a cytotoxic, quinoline-based alkaloid extracted from the Asian tree Camptotheca acuminate, with potential antineoplastic activity. Upon local application of the topotecan SR episcleral plaque to the eye, topotecan is released in a sustained manner and inhibits topoisomerase I activity by stabilizing the topoisomerase I-DNA covalent complexes during S phase of 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. The episcleral plaque allows for local delivery of topotecan for the potential treatment of retinoblastoma.

**Synonyms:** - Chemoplaque - Episcleral Topotecan - SR Topotecan Episcleral Plaque - Sustained Release Episcleral Topotecan - Sustained-release Topotecan Episcleral Plaque - Topotecan SR Episcleral Plaque - Topotecan Sustained-Release Episcleral Plaque - Transscleral Topotecan