环磷酰胺(cyclophosphamidum)又名癌得星(Endoxan),在体外无抗肿瘤作用,进入机体后须经活化始有抗癌效应。此药在肝内活化为4-羟基环磷酰胺和醛基磷酰胺,后者在正常组织中转化为无毒的代谢物,故毒性小,而在肿瘤细胞中因缺乏正常组织所具有 Cyclophosphamidum, also known as Endoxan, has no antitumor activity in vitro and must have an anti-cancer effect after activation into the body. This drug is activated in the liver as 4-hydroxy cyclophosphamide and aldehyde phosphoramidite, the latter in normal tissues into non-toxic metabolites, so the toxicity of small, but in tumor cells due to the lack of normal tissue