Loyd V. Allen, Jr., PhD
Professor Emeritus
College of Pharmacy, University of Oklahoma
Oklahoma City

Method of Preparation: Calculate the quantity of each ingredient for the amount to be prepared. Accurately weigh or measure each ingredient. Add the estradiol, estriol, and estrone to the previously combined benzyl alcohol, dimethyl sulfoxide, and absolute alcohol; mix well. Add sufficient propylene glycol to final volume and mix well. Package and label.

Use: This preparation has been used in bioidentical hormone replacement therapy.

Packaging: Package in a topical dosing device or in suitable syringes (without needles) for accurate dosing.

Labeling: Keep out of reach of children. Discard after ____ [time period]. Apply exact dose topically as directed. For external use.

Stability: A beyond-use date of up to 6 months may be used for this preparation.¹

Quality Control: Quality-control assessment can include weight/volume, specific gravity, active drug assay, color, clarity, rheologic properties/pourability, physical observation, and physical stability (discoloration, foreign materials, gas formation, mold growth).

Discussion: Estradiol (oestradiol, beta-estradiol, C₁₈H₂₄O₂, MW 272.38) occurs as white or creamy-white, odorless, hygroscopic, small crystals or as a crystalline powder. It is practically insoluble in water, but it is soluble 1 g in 28 mL of alcohol. Estradiol is sparingly soluble in vegetable oils. It should be stored in airtight containers at controlled room temperature and should be protected from light. Estriol is a naturally occurring estrogen. It occurs as a crystalline powder that is practically insoluble in water but is soluble in alcohol and vegetable oils.

Estrone is a naturally occurring steroidal estrogen. It occurs as small, white crystals or as a white to creamy-white, crystalline powder that is odorless and practically insoluble in water. Estrone is soluble to the extent of 4 mg/mL in alcohol, and it is soluble in vegetable oils. Read more.