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L6545

Sigma-Aldrich

Letrozole

≥98% (HPLC), powder, non-steroidal aromatase inhibitor

Synonym(s):

4,4′-(1H-1,2,4-Triazol-1-ylmethylene)bisbenzonitrile

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About This Item

Empirical Formula (Hill Notation):
C17H11N5
CAS Number:
112809-51-5
Molecular Weight:
285.30
MDL number:
MFCD00866241
UNSPSC Code:
51111800
PubChem Substance ID:
329817641
NACRES:
NA.77

product name

Letrozole, ≥98% (HPLC)

Quality Level

100

Assay

≥98% (HPLC)

form

powder

color

white to off-white

solubility

DMSO: >50 mg/mL

originator

Novartis

storage temp.

2-8°C

SMILES string

N#CC(C=C1)=CC=C1C(N2C=NC=N2)C3=CC=C(C#N)C=C3

InChI

1S/C17H11N5/c18-9-13-1-5-15(6-2-13)17(22-12-20-11-21-22)16-7-3-14(10-19)4-8-16/h1-8,11-12,17H

InChI key

HPJKCIUCZWXJDR-UHFFFAOYSA-N

Gene Information

human ... CYP19A1(1588)

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Application

Letrozole has been used:
  • in organoid growth assay to determine its inhibitory capacity(48)
  • to investigate steroid receptor coactivator-1 (SRC-1) mediated endogenous estrogen regulation of hippocampal PSD-95(49)
  • to determine its effects on tumor-induced hyperalgesia(50)
  • for hormonal manipulation in rats(51)
  • to study its effects on lipocalin-2 (Lcn2)(52)
  • to determine its effects on mechanical hyperalgesia and aromatase expression(53)

Biochem/physiol Actions

Letrozole acts as an adjuvant agent and is used to treat breast cancer.
Letrozole is a third generation nonsteroidal aromatase inhibitor. It is a competitive inhibitor of the aromatase enzyme system and thus inhibits the conversion of androgens to estrogens. Letrozole inhibits the aromatase enzyme by competitively binding to the heme of the cytochrome P450 subunit of the enzyme, resulting in a reduction of estrogen biosynthesis in all tissues.

Features and Benefits

This compound is featured on the Nuclear Receptors (Steroids) page of the Handbook of Receptor Classification and Signal Transduction. To browse other handbook pages, click here.
This compound was developed by Novartis. To browse the list of other pharma-developed compounds and Approved Drugs/Drug Candidates, click here.

Pictograms

Health hazard
GHS08

Signal Word

Warning

Hazard Statements

H361fd,H373

Hazard Classifications

Repr. 2 - STOT RE 2

Storage Class Code

11 - Combustible Solids

WGK

WGK 3

Flash Point(F)

Not applicable

Flash Point(C)

Not applicable

Certificates of Analysis (COA)

Search for Certificates of Analysis (COA) by entering the products Lot/Batch Number. Lot and Batch Numbers can be found on a product’s label following the words ‘Lot’ or ‘Batch’.

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Bianca Posocco et al.
PloS one, 15(2), e0228822-e0228822 (2020-02-08)
A novel LC-MS/MS method was developed for the quantification of the new cyclin dependent kinase inhibitors (CDKIs) palbociclib and ribociclib and the aromatase inhibitor letrozole used in combinatory regimen. The proposed method is appropriate to be applied in clinical practice
Natalia Lagunas et al.
Frontiers in neuroanatomy, 16, 902218-902218 (2022-07-12)
Sex steroid hormones, such as androgens and estrogens, are known to exert organizational action at perinatal periods and activational effects during adulthood on the brain and peripheral tissues. These organizational effects are essential for the establishment of biological axes responsible
Drugs for Pregnant and Lactating Women E-Book (2009)
Lijun Tan et al.
Cancers, 14(19) (2022-10-15)
Antiestrogen therapy (AET) is an alternative to cytotoxic chemotherapy for recurrent ovarian cancer, yet the often short duration of response suggests mechanisms of resistance. We previously demonstrated that tumor microenvironment interleukin-6/leukemia inhibitory factor (IL6/LIF) cytokines induce tumor cell JAK-STAT signaling
G Allevi et al.
British journal of cancer, 108(8), 1587-1592 (2013-04-13)
The objective of this study was to determine the optimal scheduling of 2.5 mg daily letrozole in neoadjuvant breast cancer patients to obtain pathological complete response (pathCR) and assess Ki-67 expression as an early predictor of response. This single institution
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