Abstract
The physical and chemical properties of the readily soluble form (RS) and standard soluble form (SS) of crystalline riboflavin which have been available from the Commercial Solvents Corp. were examined and compared with each other. Both crystals differed in the physical characteristics such as powdered x ray diffraction pattern, crystalline form under microscope, melting point and solubility in water. Any essential differences between the solutions of the two forms, however, were observed neither in the absorption spectra and the Rf values with various developing solvents, nor in the relationships between fluorescence intensity and pH and between fluorescence intensity and concentration of riboflavin. Also, the photolysis and the periodic acid oxidation gave respectively the nearly equal results for the two forms. Although the melting points of RS and SS were different, acetylated products from them had the same melting points. From the results above described, it might be confirmed that RS and SS are dimorphous.
