Formula C22H20N2O5 | Molar mass 392.404 g/mol | |
 | ||
SN-38 is an antineoplastic drug. It is the active metabolite of irinotecan (an analog of camptothecin - a topoisomerase I inhibitor) but has 1000 times more activity than irinotecan itself. In vitro cytotoxicity assays show that the potency of SN-38 relative to irinotecan varies from 2- to 2000-fold.
SN38 is formed via hydrolysis of irinotecan by carboxylesterases and metabolized via glucuronidation by UGT1A1.
The variant of UGT1A1 in ~10% of Caucasians which leads to poor metabolism of SN-38 predicts irinotecan toxicity, as it is then less easily excreted from the body in its SN-38 glucuronide form.
SN-38 and its glucuronide are lost into the bile and feces. It can cause the symptoms of diarrhoea and myelosuppression experienced by ~25% of the patients administered irinotecan.
Interactive pathway map
Click on genes, proteins and metabolites below to link to respective articles.