代谢
在吸收之后,替莫唑胺经历非酶促化学反应,转化为活性代谢物5-(3-甲基三氮唑-1-基)咪唑-4-甲酰胺(MTIC)以及二氧化碳和替莫唑胺酸性代谢物,这一过程在生理pH条件下发生,但在碱性增加时会被增强。MTIC随后与水反应,产生5-氨基咪唑-4-甲酰胺(AIC)和一个高度反应性的甲基重氮离子,即活性的烷基化物种。细胞色素P450系统在替莫唑胺代谢中仅发挥较小作用。相对于替莫唑胺的曲线下面积(AUC),MTIC和AIC的暴露量分别为2.4%和23%。
After absorption, temozolomide undergoes nonenzymatic chemical conversion to the active metabolite 5-(3-methyltriazen-1-yl) imidazole-4-carboxamide (MTIC) plus carbon dioxide and to a temozolomide acid metabolite, which occurs at physiological pH but is enhanced with increasing alkalinity. MTIC subsequently reacts with water to produce 5-aminoimidazole-4-carboxamide (AIC) and a highly reactive methyl diazonium cation, the active alkylating species. The cytochrome P450 system plays only a minor role in temozolomide metabolism. Relative to the AUC of temozolomide, the exposure to MTIC and AIC is 2.4% and 23%, respectively.
来源:DrugBank