[Betamethasone Sodium Phosphate Reference Standard (Control 881) of National Institute of Hygienic Sciences].

The raw material of betamethasone sodium phosphate was examined for preparation of the "Betamethasone Sodium Phosphate Reference Standard". Analytical results for the sample were as follows: pH 7.90; optical rotation + 100.5 degrees; IR spectrum the same as USP Reference Standard of Betamethasone Sodium Phosphate; TLC indicated no impurities, but 5 kinds of impurities were detected in small amounts by HPLC; water content 14.7%; assay 100.2% by HPLC. Based on the above results, this raw material was authorized to be the Reference Standard of the National Institute of Hygienic Sciences.