Store at -20°C. For maximum recovery of product, centrifuge the original vial prior to removing the cap.
References
Fishman, H.G, et al.: Biochemistry, 8, 4304 (1969), Ryan, Sugar, J., et al.: J. Clin. Endocrinol. Metab., 50, 137 (1980), Numazawa, M., et al.: Steroids, 38, 149 (1981), Travis, R., et al.: Breast Cancer Res., 5, 239