Definition
Riboflavin, also known as vitamin B2, is a water-soluble vitamin and is one of the B vitamins. Unlike folate and vitamin B6, which occur in several chemically related forms known as vitamers, riboflavin is only one chemical compound. It is a starting compound in the synthesis of the coenzymes flavin mononucleotide (FMN, also known as riboflavin-5-phosphate) and flavin adenine dinucleotide (FAD). FAD is the more abundant form of flavin, reported to bind to 75% of the number of flavin-dependent protein encoded genes in the all-species genome (the flavoproteome) and serves as a co-enzyme for 84% of human-encoded flavoproteins.In its purified, solid form, riboflavin is a yellow-orange crystalline powder with a slight odor and bitter taste. It is soluble in polar solvents, such as water and aqueous sodium chloride solutions, and slightly soluble in alcohols. It is not soluble in non-polar or weakly polar organic solvents such as chloroform, benzene or acetone. In solution or during dry storage as a powder, riboflavin is heat stable if not exposed to light. When heated to decompose, it releases toxic fumes containing nitric oxide. Functions
Riboflavin is essential to the formation of two major coenzymes, FMN and FAD. These coenzymes are involved in energy metabolism, cell respiration, antibody production, growth and development. Riboflavin is essential for the metabolism of carbohydrates, protein and fats. FAD contributes to conversion of tryptophan to niacin (vitamin B3) and the conversion of vitamin B6 to the coenzyme pyridoxal 5-phosphate requires FMN.
Metanx is a prescription medical food made by Alfasigma that contains L-methylfolate (as Metafolin, a calcium salt of vitamin B9), methylcobalamin (vitamin B12) and pyridoxal 5-phosphate (vitamin B6). It is a vitamin B supplement. Metanx is indicated for the dietary management of peripheral neuropathy (i.e. DPN). Ingredients
Metanx contains the following active ingredients (per capsule):

Folate
L-methylfolate (Metafolin): 3 mg
Pyridoxal 5-phosphate: 35 mg
Methylcobalamin: 2 mg

Indication and usage
Metanx is used for treating:

Painful diabetic neuropathy,
Diabetic foot ulcers,
Endothelial dysfunction  associated with diabetic peripheral neuropathy,
Hyperhomocysteinemia. == References ==