Riboflavin photodegradation products

MJ Akhtar, MA Khan, I Ahmad. High performance liquid chromatographic determination of folic acid and its photodegradation products in the presence of riboflavin. J Pharm Biomed Anal 16 95-99, 1997. 

Photolytic. When a dilute aqueous solution (1-10 mg/L) of bromacil was exposed to sunlight for 4 months, the TV-dealkylated photoproduct, 5-bromo-6-methyluracil, formed in small quantities. This compound is less stable than bromacil and upon further irradiation, the de-brominated product, 6-methyluracil was formed (Moilanen and Crosby, 1974). Acher and Dunkelblum (1979) studied the dye-sensitized photolysis of aerated aqueous solutions of bromacil using sunlight as the irradiation source. After 1 h, a mixture of diastereoisomers of 3-5ec-butyl-5-acetyl-5-hydroxyhydantoin formed in an 83% yield. In a subsequent study, another minor intermediate was identified as a 5,5 -photoproduct of 3-5ec-butyl-6-methyluracil. In this study, the rate of photooxidation increased with pH. The most effective sensitizers were riboflavin (10 ppm) and methylene blue (2-5 ppm) (Acher and Saltzman, 1980). Direct photodegradation of bromacil is not significant (Acher and Dunkelblum, 1979 Ishihara, 1963). 

Among the water-soluble vitamins subject to photodegradation during administration, thiamine, ascorbic acid, and riboflavine must be considered. A multivitamin product containing all of these vitamins was added to both 0.9% NaCl and 5% dextrose infusion solutions packaged in PVC and Clearflex containers. These admixtures were then exposed to photonic energy (2000 lux) for 24 hours and showed a rapid degradation of both riboflavine and ascorbic acid (95). 

Isoalloxazine-Containing Products from the Photodegradation of Riboflavin. Irradiation of riboflavin in deoxygenated aqueous... 

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