LAUSR

Tamoxifen and toremifene are two selective estrogen receptor modulators (SERMs) commonly used to treat breast cancer in women. Toremifene is well known as a triphenylethylene derivative. Carboxy toremifene is a common metabolite of toremifene and tamoxifen. Since 2005, the World Anti-Doping Agency (WADA) has banned the SERMs category during in and out of competition. These substances are in the S4 category in the WADA prohibited list as 'agents with anti-oestrogenic activity.' However, there is no commercially accessible carboxy-toremifene reference material in the market. This research highlights the novel synthetic procedure, the development of a carboxy toremifene HPLC method, and validation, along with detailed characterization using advanced analytical techniques using 1 H NMR, HRMS, FT-IR-ATR, and UV-visible spectroscopy. RP-HPLC-DAD method was developed and validated to assess the purity of carboxy-toremifene. Developed reference material has shown 100 % purity. Therefore, we recommend that this synthesized carboxy-toremifene may be used as reference material to strengthen the WADA-accredited lab to maintain a clean sports mission during sports competitions.