- Tirapazamine
Tirapazamine (SR-4233) is an experimental anticancer drug that is activated to a toxic radical only at very low levels of
oxygen (hypoxia). Such levels are common in human solidtumor s, a phenomenon known astumor hypoxia . Thus, tirapazamine is activated to its toxic form preferentially in the hypoxic areas of solid tumors. Cells in these regions are resistant to killing byradiotherapy and most anticancer drugs. Thus the combination of tirapazamine with conventional anticancer treatments is particularly effective.As of 2006 , tirapazamine is undergoing phase III testing in patients withhead and neck cancer and gynecological cancer, and similar trials are being undertaken for other solid tumor types.Chemically it is an aromatic heterocycle di-N-oxide. Its full chemical name is 3-amino-1,2,4-benzotriazine-1,4 dioxide. Originally it was prepared in a programme screening for new
herbicide s in 1972. Its clinical use was first described by Zeman "et al" in 1986.References
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*External links
* [http://www.clinicaltrials.gov/ct/gui/show/NCT00033410 Trial in lung cancer]
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