SN-38 is a member of the class of pyranoindolizinoquinolines that is (4S)-pyrano[3',4':6,7]indolizino[1,2-b]quinoline-3,14-dione bearing two additional ethyl substituents at positions 4 and 11 as well as two additional hydroxy substituents at positions 4 and 9. It is the active metabolite of irinotecan and is ~1000 times more active than irinotecan itself. It has a role as an antineoplastic agent, a drug metabolite, an EC 5.99.1.2 (DNA topoisomerase) inhibitor and an apoptosis inducer. It is a delta-lactone, a tertiary alcohol, a member of phenols and a pyranoindolizinoquinoline.