[Betamethasone Sodium Phosphate Reference Standard (Control 001) of National Institute of Health Sciences]

The raw material of betamethasone sodium phosphate was examined for the preparation of the "Betamethasone Sodium Phosphate Reference Standard (Control 001)". The analytical data obtained were: melting point, 207.2 degrees C; pH, 8.1; optical rotation, [alpha]D20 = +104.4 degrees; UV spectrum, lambda max of 242 nm and specific absorbance in water at 242 nm = 272.9; IR spectrum, specific absorptions at 3386.9, 1721.7, 1663.3, 1620.4, 1605.0, 1094.3, 985.8, 889.8 cm-1; free phosphoric acid, 0.3%; thin-layer chromatography, one impurity was detected until 200 micrograms; high-performance liquid chromatography, total amount of impurities estimated to be less than 0.5%; water, 9.2%. Based on the above results, the raw material was authorized as the Betamethasone Sodium Phosphate Reference Standard (Control 001) of the National Institute of Health Sciences.