Anastrozole

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Cat Number

API120511731

CAS Number

120511-73-1

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Product Detail Description Scientific Support Customer Q&A

CAS Number

120511-73-1

EINECS

601-715-6

Storage

Store at room temperature

Synonyms

Arimidex; anastrazole; Anastrozol; ZD-1033; ICI D1033; DTXSID9022607

Molecular Formula

C17H19N5

Molecular Weight

293.4

Smiles

CC(C)(C#N)C1=CC(=CC(=C1)CN2C=NC=N2)C(C)(C)C#N

Appearance

White to off-white solid powder

Melting Point

81-82°C

Boiling Point

469.7±55.0°C at 760 mmHg (Predicted)

Relative Density

1.08±0.1 (Predicted)

General Description

Anastrozole is a synthetic triazole derivative with a benzyl group and a nitrile group, belonging to the class of non-steroidal aromatase inhibitors. Its chemical structure is 2,2'-[5-(1H-1,2,4-triazol-1-ylmethyl)-1,3-phenylene]bis(2-methylpropanenitrile).

Mechanism of Action

Anastrozole acts as a selective inhibitor of the aromatase enzyme, which is responsible for the conversion of androgens to estrogens in the peripheral tissues. By blocking this enzyme, it reduces the levels of circulating estrogens, which are essential for the growth of hormone receptor-positive breast cancer cells. The drug is highly selective for aromatase and does not affect other steroidogenic enzymes.

Application

Anastrozole is indicated for the adjuvant treatment of early-stage hormone receptor-positive breast cancer in postmenopausal women and for the treatment of advanced breast cancer. It is also used for the prevention of breast cancer in high-risk women. The drug is effective in reducing the risk of recurrence and improving survival.

In a neoadjuvant trial (1,362 postmenopausal women with ER‑rich/HER2‑negative breast cancer), fulvestrant or anastrozole+fulvestrant did not improve the endocrine‑sensitive disease rate over anastrozole alone. However, in luminal B tumors, the combination produced greater Ki67 suppression. Non‑luminal tumors often showed poor Ki67 response. Aromatase inhibition remains standard, but PAM50 subtype may guide future combination strategies.

Fig. 1 CONSORT Diagram. (Ma CX, et al., 2024)

References

Ma CX, et al. Endocrine-Sensitive Disease Rate in Postmenopausal Patients With Estrogen Receptor-Rich/ERBB2-Negative Breast Cancer Receiving Neoadjuvant Anastrozole, Fulvestrant, or Their Combination: A Phase 3 Randomized Clinical Trial. JAMA Oncol. 2024;10(3):362-371.

Does Anastrozole require protection from light during long-term storage?

Yes, it is photosensitive. Light exposure can cause photodegradation of the triazole ring. Store in light-resistant containers, preferably amber glass.

What is the recommended storage temperature for Anastrozole?

Store at controlled room temperature (15-25°C). Avoid excessive heat above 30°C, which can soften the powder and accelerate degradation.

Is Anastrozole hygroscopic, and how is this managed?

It is slightly hygroscopic. Under high humidity (>70% RH), it may absorb moisture and clump. Storage in tightly sealed containers with desiccant is recommended.

How is the impurity anastrozole N-oxide (an oxidative degradation product) monitored?

This degradation product is quantified using a stability-indicating HPLC method, ensuring it remains within pharmacopoeial limits.