The present invention falls within the field of medical chemistry, and relates to a pentacyclic compound as a selective estrogen receptor down-regulator and the use thereof. In particular, provided in the present invention are a compound as shown in formula I or an isomer, a pharmaceutically acceptable salt, a solvate, a crystal or a prodrug thereof, the preparation method therefor and pharmaceutical compositions containing the compounds and the use of the compounds or compositions for treating and/or preventing estrogen receptor-associated diseases. The compound of the present invention has an even better anti-tumour activity, a longer dosing interval and fewer side effects, and seems to be very promising as a therapeutic agent against breast cancer.本發明屬於醫藥化學領域,涉及一類作為選擇性雌激素受體下調節劑的五環類化合物及其應用,具體地,本發明提供式I所示的化合物或其異構體、藥學上可接受的鹽、溶劑化物、結晶或前藥,它們的製備方法以及含有這些化合物的藥物組合物和這些化合物或組合物用於治療和/或預防雌激素受體相關的疾病的用途。本發明的化合物具有更加優異的抗腫瘤活性,給藥間隔更長,副作用更小,非常有希望成為乳腺癌治療劑。
