代谢
他莫昔芬可以通过羟基化转变为α-羟基他莫昔芬,然后被葡萄糖醛酸化或通过磺基转移酶2A1进行硫酸盐结合。他莫昔芬还可以通过黄素单加氧酶1和3进行N-氧化,生成他莫昔芬N-氧化物。他莫昔芬通过CYP2D6、CYP1A1、CYP1A2、CYP3A4、CYP1B1、CYP2C9、CYP2C19和CYP3A5进行N-去烷基化,生成N-去甲基他莫昔芬。N-去甲基他莫昔芬可以被硫酸盐结合形成N-去甲基他莫昔芬硫酸盐,通过CYP2D6的4-羟基化生成末端他莫昔芬,或者再次通过CYP3A4和CYP3A5进行N-去烷基化生成N,N-二去甲基他莫昔芬。N,N-二去甲基他莫昔芬发生取代反应形成他莫昔芬代谢物Y,然后通过醚裂解生成代谢物E,该代谢物可以通过磺基转移酶1A1和1E1进行硫酸盐结合或进行O-葡萄糖醛酸化。他莫昔芬还可以通过CYP2D6、CYP2B6、CYP3A4、CYP2C9和CYP2C19进行4-羟基化,生成4-羟基他莫昔芬。4-羟基他莫昔芬可以通过UGT1A8、UGT1A10、UGT2B7和UGT2B17的葡萄糖醛酸化生成他莫昔芬葡萄糖醛酸苷,通过磺基转移酶1A1和1E1的硫酸盐结合生成4-羟基他莫昔芬硫酸盐,或者通过CYP3A4和CYP3A5的N-去烷基化生成末端他莫昔芬。末端他莫昔芬发生去甲基化生成诺末端他莫昔芬,通过磺基转移酶1A1和1E1的可逆硫酸盐结合反应生成4-羟基他莫昔芬硫酸盐,通过磺基转移酶2A1的硫酸盐结合生成4-末端他莫昔芬硫酸盐,或者通过UGT1A8、UGT1A10、UGT2B7或UGT2B15的葡萄糖醛酸化生成他莫昔芬葡萄糖醛酸苷。
Tamoxifen can by hydroxylated to α-hydroxytamoxifen which is then glucuronidated or undergoes sulfate conjugation by sulfotransferase 2A1. Tamoxifen can also undergo N-oxidation by flavin monooxygenases 1 and 3 to tamoxifen N-oxide. Tamoxifen is N-dealkylated to N-desmethyltamoxifen by CYP2D6, CYP1A1, CYP1A2, CYP3A4, CYP1B1, CYP2C9, CYP2C19, and CYP3A5. N-desmethyltamoxifen can be sulfate conjugated to form N-desmethyltamoxifen sulfate, 4-hydroxylated by CYP2D6 to form endoxifen, or N-dealkylated again by CYP3A4 and CYP3A5 to N,N-didesmethyltamoxifen. N,N-didesmethyltamoxifen undergoes a substitution reaction to form tamoxifen metabolite Y, followed by ether cleavage to metabolite E, which can then be sulfate conjugated by sulfotransferase 1A1 and 1E1 or O-glucuronidated. Tamoxifen can also by 4-hydroxylated by CYP2D6, CYP2B6, CYP3A4, CYP2C9, and CYP2C19 to form 4-hydroxytamoxifen. 4-hydroxytamoxifen can undergo glucuronidation by UGT1A8, UGT1A10, UGT2B7, and UGT2B17 to tamoxifen glucuronides, sulfate conjugation by sulfotransferase 1A1 and 1E1 to 4-hydroxytamoxifen sulfate, or N-dealkylation by CYP3A4 and CYP3A5 to endoxifen. Endoxifen undergoes demethylation to norendoxifen, a reversible sulfate conjugation reaction via sulfotransferase 1A1 and 1E1 to 4-hydroxytamoxifen sulfate, sulfate conjugation via sulfotransferase 2A1 to 4-endoxifen sulfate, or glucuronidation via UGT1A8, UGT1A10, UGT2B7, or UGT2B15 to tamoxifen glucuronides.
来源:DrugBank