which precursor ion and fragment ion data were obtained simultaneously to screen novel phase II EXE metabolites in urine specimens from women taking EXE. Two major metabolites predicted to be cysteine conjugates of EXE and 17β-DHE by elemental composition were identified. The structures of the two metabolites were confirmed to be 6-methylcysteinylandrosta-1,4-diene-3,17-dione (6-EXE-cys) and 6-methylcysteinylandrosta-1
Exemestane(EXE)是一种芳香酶
抑制剂,用于预防和治疗
雌激素受体阳性乳腺癌。尽管EXE已知的主要代谢途径是还原形成活性17β-二氢EXE(17β-DHE)和随后的
葡糖醛酸化为17β-羟基-EXE-17-O-β-
D-葡糖醛酸(17β-DHE-Gluc) ,以前的研究表明,
依西美坦存在其他主要代谢产物。在本研究中,采用
液相色谱-质谱(LC-MS)方法以M
SE模式获取准确的质量数据,其中同时获得前体离子和碎片离子数据,以筛选尿液样本中新的II期EXE代谢物妇女服用EXE。通过元素组成鉴定了两种主要的代谢物,它们被预测为EXE和17β-DHE的半胱
氨酸结合物。两种代谢物的结构被确认为6-甲基半胱
氨酸基罗斯塔-1,4-二烯-3,17-二酮(6-EXE-cys)和6-甲基半胱
氨酸基罗斯塔-1,4-二烯-17β-羟基-3-酮(6-17β-DHE-cys)与
化学合成的对应物比较后。两者都在体外通