Record Information
Version1.0
Creation Date2014-09-11 02:06:08 UTC
Update Date2026-03-31 19:03:56 UTC
Accession NumberCHEM003672
Identification
Common NameTamoxifen
ClassSmall Molecule
DescriptionTamoxifen 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.
Contaminant Sources
  • HMDB Contaminants - Urine
  • IARC Carcinogens Group 1
  • My Exposome Chemicals
  • STOFF IDENT Compounds
  • T3DB toxins
  • ToxCast & Tox21 Chemicals
Contaminant Type
  • Amine
  • Antineoplastic Agent, Hormonal
  • Bone Density Conservation Agent
  • Drug
  • Estrogen Antagonist
  • Ether
  • Metabolite
  • Organic Compound
  • Selective Estrogen Receptor Modulator
  • Synthetic Compound
Chemical Structure
Thumb
Synonyms
ValueSource
(Z)-2-(4-(1,2-Diphenyl-1-butenyl)phenoxy)-N,N-dimethylethanamineChEBI
(Z)-2-(Para-(1,2-diphenyl-1-butenyl)phenoxy)-N,N-dimethylamineChEBI
1-p-beta-Dimethylaminoethoxyphenyl-trans-1,2-diphenylbut-1-eneChEBI
1-Para-beta-dimethylaminoethoxyphenyl-trans-1,2-diphenylbut-1-eneChEBI
Apo-tamoxChEBI
CitofenChEBI
CrisafenoChEBI
DiemonChEBI
Gen-tamoxifenChEBI
IstubolChEBI
NoltamChEBI
NourytamChEBI
OncomoxChEBI
RetaximChEBI
TamofenChEBI
TamoneChEBI
TamoxastaChEBI
TamoxifeneChEBI
TamoxifenoChEBI
TamoxifenumChEBI
trans-TamoxifenChEBI
ValodexChEBI
ZemideChEBI
TamoplexKegg
1-p-b-Dimethylaminoethoxyphenyl-trans-1,2-diphenylbut-1-eneGenerator
1-p-Β-dimethylaminoethoxyphenyl-trans-1,2-diphenylbut-1-eneGenerator
1-Para-b-dimethylaminoethoxyphenyl-trans-1,2-diphenylbut-1-eneGenerator
1-Para-β-dimethylaminoethoxyphenyl-trans-1,2-diphenylbut-1-eneGenerator
Tamoxifen citrateHMDB
NolvadexHMDB
NovaldexHMDB
Savient brand OF tamoxifen citrateHMDB
Citrate, tamoxifenHMDB
TomaxithenHMDB
SoltamoxHMDB
ZitazoniumHMDB
Chemical FormulaC26H29NO
Average Molecular Mass371.515 g/mol
Monoisotopic Mass371.225 g/mol
CAS Registry Number10540-29-1
IUPAC Name(2-{4-[(1Z)-1,2-diphenylbut-1-en-1-yl]phenoxy}ethyl)dimethylamine
Traditional Nametamoxifen
SMILESCC\C(=C(/C1=CC=CC=C1)C1=CC=C(OCCN(C)C)C=C1)C1=CC=CC=C1
InChI IdentifierInChI=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-
InChI KeyNKANXQFJJICGDU-QPLCGJKRSA-N
Chemical Taxonomy
Description belongs to the class of organic compounds known as stilbenes. These are organic compounds containing a 1,2-diphenylethylene moiety. Stilbenes (C6-C2-C6 ) are derived from the common phenylpropene (C6-C3) skeleton building block. The introduction of one or more hydroxyl groups to a phenyl ring lead to stilbenoids.
KingdomOrganic compounds
Super ClassPhenylpropanoids and polyketides
ClassStilbenes
Sub ClassNot Available
Direct ParentStilbenes
Alternative Parents
Substituents
  • Stilbene
  • Diphenylmethane
  • Phenylpropane
  • Phenoxy compound
  • Phenol ether
  • Alkyl aryl ether
  • Benzenoid
  • Monocyclic benzene moiety
  • Tertiary aliphatic amine
  • Tertiary amine
  • Ether
  • Organopnictogen compound
  • Hydrocarbon derivative
  • Organooxygen compound
  • Organonitrogen compound
  • Organic nitrogen compound
  • Amine
  • Organic oxygen compound
  • Aromatic homomonocyclic compound
Molecular FrameworkAromatic homomonocyclic compounds
External Descriptors
Biological Properties
StatusDetected and Not Quantified
OriginExogenous
Cellular Locations
  • Cytoplasm
  • Membrane
Biofluid LocationsNot Available
Tissue LocationsNot Available
PathwaysNot Available
ApplicationsNot Available
Biological RolesNot Available
Chemical RolesNot Available
Physical Properties
StateSolid
AppearanceWhite powder.
Experimental Properties
PropertyValue
Melting Point97°C
Boiling PointNot Available
Solubility0.000167 mg/mL at 25°C
Predicted Properties
PropertyValueSource
Water Solubility0.001 g/LALOGPS
logP5.93ALOGPS
logP6.35ChemAxon
logS-5.6ALOGPS
pKa (Strongest Basic)8.76ChemAxon
Physiological Charge1ChemAxon
Hydrogen Acceptor Count2ChemAxon
Hydrogen Donor Count0ChemAxon
Polar Surface Area12.47 ŲChemAxon
Rotatable Bond Count8ChemAxon
Refractivity128.43 m³·mol⁻¹ChemAxon
Polarizability44.19 ųChemAxon
Number of Rings3ChemAxon
Bioavailability1ChemAxon
Rule of FiveNoChemAxon
Ghose FilterNoChemAxon
Veber's RuleYesChemAxon
MDDR-like RuleYesChemAxon
Spectra
Spectra
Spectrum TypeDescriptionSplash KeyView
Predicted GC-MSPredicted GC-MS Spectrum - GC-MS (Non-derivatized) - 70eV, Positivesplash10-0a4i-9144000000-3359f7eb514ced73f022Spectrum
Predicted GC-MSPredicted GC-MS Spectrum - GC-MS (Non-derivatized) - 70eV, PositiveNot AvailableSpectrum
LC-MS/MSLC-MS/MS Spectrum - , positivesplash10-004i-3972000000-38c8a6cb6c6f2505438bSpectrum
LC-MS/MSLC-MS/MS Spectrum - LC-ESI-QFT , positivesplash10-00di-9006000000-8443975759913521d9cdSpectrum
LC-MS/MSLC-MS/MS Spectrum - 40V, Positivesplash10-004i-0890000000-7d32643701e60529d39bSpectrum
LC-MS/MSLC-MS/MS Spectrum - 40V, Positivesplash10-004i-0890000000-fd906e590fdf543b6899Spectrum
LC-MS/MSLC-MS/MS Spectrum - 35V, Positivesplash10-00di-9006000000-f84f79502277004ac040Spectrum
LC-MS/MSLC-MS/MS Spectrum - 30V, Positivesplash10-00di-0349000000-4205fab50150d73f24d6Spectrum
LC-MS/MSLC-MS/MS Spectrum - 10V, Positivesplash10-00di-0009000000-a245a8f75fd67b24d125Spectrum
LC-MS/MSLC-MS/MS Spectrum - 20V, Positivesplash10-00di-0009000000-cf65e058d06ec3f0c2d2Spectrum
LC-MS/MSLC-MS/MS Spectrum - 15V, Positivesplash10-00di-0009000000-e2e1640918ad010e0f15Spectrum
LC-MS/MSLC-MS/MS Spectrum - 50V, Positivesplash10-004i-0980000000-655d348a80f2ddaa2113Spectrum
LC-MS/MSLC-MS/MS Spectrum - 30V, Positivesplash10-00di-9002000000-1725fbd9626a212cad69Spectrum
LC-MS/MSLC-MS/MS Spectrum - 45V, Positivesplash10-00di-9000000000-b52da730d05051dbfa6cSpectrum
LC-MS/MSLC-MS/MS Spectrum - 75V, Positivesplash10-00di-9000000000-fdf49fca2d2b0e8c78d1Spectrum
LC-MS/MSLC-MS/MS Spectrum - 60V, Positivesplash10-00di-9000000000-a8956f34f19e5a62993cSpectrum
LC-MS/MSLC-MS/MS Spectrum - 40V, Positivesplash10-00dl-9100000000-1fb3454c775df7c7ed05Spectrum
LC-MS/MSLC-MS/MS Spectrum - 20V, Positivesplash10-00di-9116000000-3913ede2827c62364821Spectrum
LC-MS/MSLC-MS/MS Spectrum - 10V, Positivesplash10-00di-9000000000-c281f0985f57fc828737Spectrum
LC-MS/MSLC-MS/MS Spectrum - 90V, Positivesplash10-00di-9100000000-60d346ff207483b51e77Spectrum
LC-MS/MSLC-MS/MS Spectrum - 50V, Positivesplash10-004i-0980000000-ac0d9364dc824e030b74Spectrum
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 10V, Positivesplash10-00di-1249000000-300a60fd4d5ac611b49cSpectrum
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 20V, Positivesplash10-00di-9464000000-b29d0ae97047e89de42dSpectrum
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 40V, Positivesplash10-0600-9561000000-bb923af5238f4028d8b1Spectrum
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 10V, Negativesplash10-00di-1029000000-e34a1955366e5613bde8Spectrum
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 20V, Negativesplash10-006t-1095000000-1eb06b0cfd7f34bf9808Spectrum
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 40V, Negativesplash10-000t-2190000000-7cebd77678fb7be2a3e5Spectrum
Toxicity Profile
Route of ExposureWhen 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.
Mechanism of ToxicityTamoxifen 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.
MetabolismHepatic. 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.
Toxicity ValuesNot Available
Lethal DoseNot Available
Carcinogenicity (IARC Classification)1, carcinogenic to humans. (7)
Uses/SourcesTamoxifen is indicated for the treatment of metastatic breast cancer in women and men and ductal carcinoma in Situ.
Minimum Risk LevelNot Available
Health EffectsNot Available
SymptomsSigns observed at the highest doses following studies to determine LD50 in animals were respiratory difficulties and convulsions.
TreatmentNot Available
Concentrations
Not Available
DrugBank IDDB00675
HMDB IDHMDB0014813
FooDB IDNot Available
Phenol Explorer IDNot Available
KNApSAcK IDNot Available
BiGG IDNot Available
BioCyc IDNot Available
METLIN IDNot Available
PDB IDNot Available
Wikipedia LinkTamoxifen
Chemspider ID2015313
ChEBI ID41774
PubChem Compound ID2733526
Kegg Compound IDC07108
YMDB IDNot Available
ECMDB IDNot Available
References
Synthesis Reference

Chengjian Mao, “Tamoxifen and 4-hydroxytamoxifen-activated system for regulated production of proteins in eukaryotic cells.” U.S. Patent US20030199022, issued October 23, 2003.

MSDSLink
General References
1. Jordan VC: Fourteenth Gaddum Memorial Lecture. A current view of tamoxifen for the treatment and prevention of breast cancer. Br J Pharmacol. 1993 Oct;110(2):507-17.
2. Howell A, Cuzick J, Baum M, Buzdar A, Dowsett M, Forbes JF, Hoctin-Boes G, Houghton J, Locker GY, Tobias JS: Results of the ATAC (Arimidex, Tamoxifen, Alone or in Combination) trial after completion of 5 years' adjuvant treatment for breast cancer. Lancet. 2005 Jan 1-7;365(9453):60-2.
3. Steiner AZ, Terplan M, Paulson RJ: Comparison of tamoxifen and clomiphene citrate for ovulation induction: a meta-analysis. Hum Reprod. 2005 Jun;20(6):1511-5. Epub 2005 Apr 21.
4. Jordan VC: Tamoxifen (ICI46,474) as a targeted therapy to treat and prevent breast cancer. Br J Pharmacol. 2006 Jan;147 Suppl 1:S269-76.
5. van Bommel EF, Hendriksz TR, Huiskes AW, Zeegers AG: Brief communication: tamoxifen therapy for nonmalignant retroperitoneal fibrosis. Ann Intern Med. 2006 Jan 17;144(2):101-6.
6. Graumann K, Jungbauer A: Agonistic and synergistic activity of tamoxifen in a yeast model system. Biochem Pharmacol. 2000 Jan 15;59(2):177-85.
7. FDA label
8. https://www.ncbi.nlm.nih.gov/pubmed/?term=14681337
9. https://www.ncbi.nlm.nih.gov/pubmed/?term=14709804
10. https://www.ncbi.nlm.nih.gov/pubmed/?term=18348622
11. https://www.ncbi.nlm.nih.gov/pubmed/?term=7688593