[Methoxalene Reference Standard (Control 901) of National Institute of Hygienic Sciences].

The raw material of methoxalene was examined for the preparation of the "Methoxalene Reference Standard". Analytical data obtained were as follows: ultraviolet spectrum, lambda max = 300, 249 and 218 nm; absorbance, E1cm(1%) (300 nm) = 559; infrared spectrum, same as that of USP Reference Standard of Methoxalene; melting point, 148 degrees C; thin-layer chromatography, no impurities were detected until 50 micrograms; high-performance liquid chromatography (HPLC), no impurities were detected, water, 0.04%; assay, 99.9% by absorbance method and 100.4% by the HPLC method in terms of the USP Reference Standard. Based on the above results, this raw material was authorized to be the Reference Standard of the National Institute of Hygienic Sciences.