MICROSPHERES OF ESTRADIOL AND CHOLESTEROL

摘要

The present invention relates to microspheres of estradiol and cholesterol in a 1:1 molar ratio, having an ERD of about 6% or less. In a preferred embodiment of the invention the microspheres having an X-ray crystallographic spectra substantially the same as Figure 22; wherein the estradiol consists of a hemicrystalline form where about 50-60% is amorphous and about 40-50% is crystalline. Alternately the estradiol is in a hemicrystalline form that is about 55% amorphous and about 45% crystalline. The estradiol is 17-&bgr;-estradiol. According to the invention the microspheres can be parenterally administered once a month or less often.