Estetrol (E4) is a naturally occurring estrogenic steroid hormone and a selective estrogen receptor modulator with estrogenic activity. It is an active pharmaceutical ingredient used in hormonal pharmaceutical formulations, particularly in combination with other hormonal agents.
Estetrol is produced naturally by the human fetal liver during pregnancy and has a distinct pharmacological profile compared with other commonly used estrogens.
Estetrol, also known as E4, is a steroidal estrogen belonging to the estrogen hormone family. It is structurally characterized by four hydroxyl groups and is distinguished from estradiol and estriol by its specific receptor activity.
CAS Number: 15183-36-7
Molecular Formula: C₁₈H₂₄O₄
Molecular Weight: 304.38 g/mol
Estetrol binds to estrogen receptors (ERα and ERβ) and produces estrogenic effects in target tissues.
Its pharmacological activity is associated with:
Estetrol has a distinctive receptor profile compared with other estrogens and is being utilized in modern hormonal pharmaceutical formulations.
Estetrol is used as an API in pharmaceutical formulations, particularly for:
The exact approved indication depends on the final pharmaceutical formulation and applicable regulatory labeling.
Estetrol is a steroidal estrogen API with defined stereochemistry and purity requirements. As a pharmaceutical-grade active ingredient, its identity, assay, related substances, stereochemical purity and other quality attributes should be controlled according to the applicable approved specification.
Pharmaceutical-grade Estetrol should comply with the applicable approved specification and relevant regulatory requirements.
Typical quality-control parameters may include:
A qualified supplier should provide Certificate of Analysis (CoA), specification sheet, SDS/MSDS, batch traceability and applicable regulatory documentation.
Estetrol should be stored in a tightly closed container, protected from excessive moisture, heat and direct light, according to the applicable approved storage and stability requirements.
| Parameter | Specification |
|---|---|
| Appearance | White to off-white crystalline powder |
| Identification | IR & HPLC compliant |
| Assay (HPLC) | 98.0% – 102.0% |
| Loss on Drying | NMT 1.0% |
| Residue on Ignition | NMT 0.5% |
| Heavy Metals | NMT 20 ppm |
| pH (1% Solution) | 5.5 – 6.5 |
| Individual Impurity | NMT 0.5% |
| Total Impurities | NMT 1.0% |
| Water Content | NMT 1.0% |