Vitamin B2 (Riboflavin)

Riboflavin, also listed as vitamin B2 or lactoflavin, is a yellow to orange-yellow crystalline powder of formula C17H20N4O6, molecular weight 376.37, CAS 83-88-5. Thovek supplies it against USP/NF, European Pharmacopoeia monograph 0292, BP, JP, IP and FCC requirements, with an assay of 98.0-102.0% calculated on the dried basis and a specific rotation of -115 to -135 degrees. It is very slightly soluble in water — roughly one gram in three to twenty litres depending on the crystal form — practically insoluble in ethanol, chloroform and ether, and soluble in dilute alkali. The powder darkens from about 240 C and melts with decomposition near 280 C. Riboflavin is the precursor of the coenzymes flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD), which act as hydrogen carriers in the oxidation-reduction reactions of normal energy metabolism; this established nutrient function is the basis for its use in supplements, premixes and fortified foods. The same chromophore gives the material its intense yellow shade, and riboflavin is separately listed as a colour under E 101(i) / INS 101(i) for food and beverage use. It is markedly light-sensitive in solution and in thin layers, so weighing, blending, granulation and filling are normally carried out under subdued light. Commercial riboflavin is made either by fermentation, typically with Ashbya gossypii or Bacillus subtilis, or by chemical synthesis; the route is stated on the certificate of analysis. Standard supply is a fine powder passing 60 mesh with approximately 95% through 80 mesh, and micronised grades or spray-dried feed grades at nominally 80% riboflavin can be produced to order. Each lot is released against assay, loss on drying, residue on ignition, lumiflavin, specific rotation, elemental impurities and microbiological limits. Export documentation covers CoA, MSDS, allergen, GMO, BSE/TSE and halal/kosher statements, with certificate of origin and any certificate of free sale arranged for the destination market.