Buccal Absorption of α-Estradiol in Propylene Glycol

In the treatment of estrogen deficiency states, it is frequently necessary to administer estrogens for prolonged periods of time.

The usual method of administration consists of subcutaneous or intramuscular injections. It would be highly advantageous if one could administer estrogens in effective amounts without submitting the patient to the annoyance of repeated injections. Although it has been shown that estrogens are absorbed through the skin and the intestinal tract, neither method is satisfactory for therapeutic purposes.

In the present communication, we wish to describe a method for administering estrogens which is both simple and effective. It consists of sublingual administration of α-estradiol in a propylene glycol solution.∗ The solution contains 0.5 mg of a-estradiol per cc of propylene glycol. Four drops are placed under the tongue and the patient is instructed not to swallow for five minutes. This can be done several times a day.

The present study was performed on a series of 8 women with objective evidence (demonstrated by vaginal smearsf and vaginal biopsies) of estrogen deficiency. The hormone was administered 3 to 6 times a day. Vaginal smears were taken daily and vaginal biopsies at intervals of 1 to 2 weeks.

Results. Characteristic vaginal smear changes indicating an estrogen effect were noted as early as 4 days after the beginning of hormone administration, with daily doses of 0.3 mg of α-estradiol (Figs. 1 and 2). Vaginal biopsies at the end of one week showed definite evidence of estrogen stimulation. No untoward effects were noted as a result of the propylene glycol absorption.