title: Effect of riboflavin on the photolysis of folic acid in aqueous solution.
abstract: A study of the photolysis of folic acid in aqueous solution by visible radiation in the presence of riboflavin has been made. The second-order rate constants for the bimolecular interaction of folic acid and riboflavin have been determined in the pH range 4.0-9.0. The rate pH profile shows a gradual increase in the rate up to pH 6.2 (pHmax) followed by a decrease up to pH 9.0, depending upon the susceptibility of ionic species involved in the interaction. The rate of photolysis varies from 0.50 x 10(3) M(-1) min(-1) (pH 9.0) and 0.63 x 10(3) M(-1) min(-1) (pH 4.0) to 3.0 x 10(3) M(-1) min(-1) (pH 6.2) in the pH range studied. A HPLC method has been used for the assay of folic acid and its photoproducts, pterine-6-carboxylic acid and p-aminobenzoyl-L-glutamic acid in the presence of riboflavin.
authors.affiliation: Research and Development Laboratories, GlaxoWellcome Pakistan Ltd., Karachi.
authors.forename: M J
authors.initials: MJ
authors.lastname: Akhtar
authors.forename: M A
authors.initials: MA
authors.lastname: Khan
authors.forename: I
authors.initials: I
authors.lastname: Ahmad
mesh_terms: D002851:Chromatography, High Pressure Liquid; D005492:Folic Acid / Q000032:analysis*; D006397:Hematinics / Q000032:analysis*; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D010782:Photolysis / Q000187:drug effects*; D017319:Photosensitizing Agents / Q000494:pharmacology*; D012044:Regression Analysis; D012256:Riboflavin / Q000494:pharmacology*; D012996:Solutions
chemical_list: D006397:Hematinics; D017319:Photosensitizing Agents; D012996:Solutions; D005492:Folic Acid; D012256:Riboflavin