[Betamethasone Reference Standard (Control 951) of the National Institute of Health Sciences].

The raw material of betamethasone was tested for preparation of the "Betamethasone Reference Standard (Control 951)". Analytical data obtained were as follows: loss on drying, 0.0%; infrared spectrum, the same as that of the JP Betamethasone Reference Standard (Control 845); thin-layer chromatography, no impurity was detected; high-performance liquid chromatography (HPLC), two kinds of impurities were detected and the total amount was estimated to be 0.16 +/- 0.01% (n = 3); assay, 100.0% by HPLC. Based on the above results, the raw material was authorized as the JP Betamethasone Reference Standard (Control 951).