[Estradiol Reference Standard (Control 961) of National Institute of Health Sciences]

The raw material for estradiol was examined for preparation of the "Estradiol Reference Standard (Control 961)" of National Institute of Health Sciences. Analytical data obtained were as follows: melting point, 179.1 degrees C; UV spectrum, lambda max = 281 nm; IR spectrum, the same as that of the Estradiol Reference Standard of National Institute of Health Sciences (Control 931); optical rotation, [alpha]20D = +79.5 degrees; thin-layer chromatography, one impurity was detected; high-performance liquid chromatography (HPLC), a trace amount of three impurities were detected; loss on drying, 3.17%; assay, 99.4% by UV spectrophotometry and 99.0% by HPLC. Based on the above results, the raw material was authorized as the Estradiol Reference Standard (Control 961) of National Institute of Health Sciences.