estriol and its Impurities
A natural steroidal estrogen, Estriol is also known as 16α-hydroxyestradiol. It is used as a hormone replacement therapy in menopausal symptoms. It is produced by the ovaries during pregnancy. It is an agonist of both of the estrogen receptors (ER), ERα and ERβ. Reference standards of Estriol API, and its pharmacopeial, non pharmacopeial impurities, and stable isotopes are listed below.

![(17β)-3,17-Bis[(tetrahydro-2H-pyran-2-yl)oxy]-est PA 05 0211011](https://www.pharmaffiliates.com/pimages/PA050211011.jpg)
(17β)-3,17-Bis[(tetrahydro-2H-pyran-2-yl)oxy]-estra-1,3,5(10)-trien-6-ol (Mixture of Diasteromers)
(17β)-3,17-Bis[(tetrahydro-2H-pyran-2-yl)oxy]-estra-1,3,5(10)-trien-6-ol (Mixture of Diasteromers)
Catalogue No.:PA 05 0211011
CAS :
122566-22-7
Molecular Formula : C28H40O5
Molecular Weight : 456.62