Notes: Bazedoxifene-d4 is intended for use as an internal standard for the quantification of bazedoxifene (Item No. 15005) by GC- or LC-MS. Bazedoxifene is a third generation selective estrogen receptor modulator (SERM). It is an indole-based ER ligand that binds to both ERα (IC50 = 26 nM) and ERβ (IC50 = 99 nM).{22645} Bazedoxifene antagonizes 17β-estradiol-dependent MCF-7 and T47D breast cancer cell proliferation in vitro as well as hormone-independent growth of MCF-7:5C cells that are resistant to long-term estrogen deprivation (80% reduction with 10 nM).{22646} It has been shown to arrest cell cycling by downregulating cyclin D1 and ERα.