4769 T3D4714 Tamoxifen Tamoxifen is only found in individuals that have used or taken this drug. It is one of the selective estrogen receptor modulators with tissue-specific activities. Tamoxifen acts as an anti-estrogen (inhibiting agent) in the mammary tissue, but as an estrogen (stimulating agent) in cholesterol metabolism, bone density, and cell proliferation in the endometrium. Tamoxifen binds to estrogen receptors (ER), inducing a conformational change in the receptor. This results in a blockage or change in the expression of estrogen dependent genes. The prolonged binding of tamoxifen to the nuclear chromatin of these results in reduced DNA polymerase activity, impaired thymidine utilization, blockade of estradiol uptake, and decreased estrogen response. It is likely that tamoxifen interacts with other coactivators or corepressors in the tissue and binds with different estrogen receptors, ER-alpha or ER-beta, producing both estrogenic and antiestrogenic effects. 10540-29-1 2733526 C26H29NO White powder. 97°C 0.000167 mg/mL at 25°C When a single oral dose of 20 mg is given, the average peak plasma concentration (Cmax) is 40 ng/mL which occurred approximately 5 hours after dosing (Tmax). The Cmax of N-desmethyl tamoxifen is 15 ng/mL. Steady-state concentrations for tamoxifen is achieved in 4 weeks, while steady-state concentrations for N-desmethyl tamoxifen is achieved in 8 weeks. Tamoxifen is a nonsteroidal agent that binds to estrogen receptors (ER), inducing a conformational change in the receptor. This results in a blockage or change in the expression of estrogen dependent genes. The prolonged binding of tamoxifen to the nuclear chromatin of these results in reduced DNA polymerase activity, impaired thymidine utilization, blockade of estradiol uptake, and decreased estrogen response. It is likely that tamoxifen interacts with other coactivators or corepressors in the tissue and binds with different estrogen receptors, ER-alpha or ER-beta, producing both estrogenic and antiestrogenic effects. Hepatic. Tamoxifen is extensively metabolized after oral administration. N-Desmethyl-tamoxifen is the major metabolite found in plasma. N-Desmethyl-tamoxifen's activity is similar to tamoxifen. 4-hydroxy-tamoxifen and a side chain primary alcohol derivative of tamoxifen have been identified as minor metabolites in plasma. 4-Hydroxy-tamoxifen formation is catalyzed mainly by cytochrome P450 (CYP) 2D6, and also by CYP2C9 and 3A4. At high tamoxifen concentrations, CYP2B6 also catalyzes 4-hydroxylation of the parent drug. 4-Hydroxy-tamoxifen possesses 30- to 100-times greater affinity for the estrogen receptor and 30- to 100-times greater potency at inhibiting estrogen-dependent cell proliferation compared to tamoxifen. It is also metabolized by flavin monooxygenases FMO1 and FMO3 to form tamoxifen-N-oxide. Route of Elimination: 65% of the dose was excreted from the body over 2 weeks in which fecal excretion was the primary route of elimination. Tamoxifen is excreted mainly as polar conjugates, with unchanged drug and unconjugated metabolites accounting for less than 30% of the total fecal radioactivity. Half Life: The decline in tamoxifen plasma concentrations is biphasic with a terminal elimination half-life of approximately 5 to 7 days. The estimated half-life of N-desmethyl tamoxifen is 14 days. 1, carcinogenic to humans. (L135) Tamoxifen is indicated for the treatment of metastatic breast cancer in women and men and ductal carcinoma in Situ. Signs observed at the highest doses following studies to determine LD<sub>50</sub> in animals were respiratory difficulties and convulsions. 2014-09-11T02:06:08Z 2026-03-31T19:03:56Z http://en.wikipedia.org/wiki/Tamoxifen C07108 9396 DB00675 CTX true CC\C(=C(/C1=CC=CC=C1)C1=CC=C(OCCN(C)C)C=C1)C1=CC=CC=C1 C26H29NO InChI=1S/C26H29NO/c1-4-25(21-11-7-5-8-12-21)26(22-13-9-6-10-14-22)23-15-17-24(18-16-23)28-20-19-27(2)3/h5-18H,4,19-20H2,1-3H3/b26-25- NKANXQFJJICGDU-QPLCGJKRSA-N 371.5146 371.224914555 Exogenous Solid 7.1 HMDB14813 CHEMBL83 2015313 <p>Chengjian Mao, &#8220;Tamoxifen and 4-hydroxytamoxifen-activated system for regulated production of proteins in eukaryotic cells.&#8221; U.S. Patent US20030199022, issued October 23, 2003.</p> CHEM003672 DTXSID1034187 NS00010353 (2-{4-[(1Z)-1,2-diphenylbut-1-en-1-yl]phenoxy}ethyl)dimethylamine