Riboflavin, also known as Vitamin B2 or Lactoflavin, is a water-soluble vitamin and an essential precursor of the flavin coenzymes FMN (flavin mononucleotide) and FAD (flavin adenine dinucleotide). Riboflavin is identified by CAS No. 83-88-5, molecular formula C₁₇H₂₀N₄O₆, and molecular weight 376.36 g/mol.
The USP monograph specifies that Riboflavin contains 98.0% to 102.0% of riboflavin calculated on the dried basis. The European Pharmacopoeia/BP monograph specifies 97.0% to 103.0% on the dried substance.
Riboflavin is a yellow to orange-yellow crystalline substance. It is very slightly soluble in water and practically insoluble in ethanol. It is sensitive to light, and its solutions can deteriorate on exposure to light, particularly under alkaline conditions.
The substance exhibits characteristic greenish-yellow fluorescence and defined optical-rotation and UV-absorbance characteristics used for pharmacopoeial identification and quality control.
| Parameter | Details |
|---|---|
| Product Name | Riboflavin |
| Synonyms | Vitamin B2, Riboflavine, Lactoflavin |
| CAS Number | 83-88-5 |
| Molecular Formula | C₁₇H₂₀N₄O₆ |
| Molecular Weight | 376.36 g/mol |
| Molecular Type | Small-Molecule Vitamin |
| Therapeutic/Nutritional Class | Vitamin B2 |
| Appearance | Yellow to orange-yellow crystalline powder |
| Melting / Decomposition | Approximately 290°C with decomposition |
| Specific Rotation | −115° to −135° |
| Water Solubility | Very slightly soluble; approximately 0.01 g/100 mL at 25°C |
| Ethanol Solubility | Practically insoluble |
| Storage | Tight, light-resistant containers |
JP XVII describes Riboflavin as yellow to orange-yellow crystals, very slightly soluble in water, practically insoluble in ethanol and decomposing at approximately 290°C.
Riboflavin is used as an active nutritional ingredient and pharmaceutical substance for the prevention and treatment of vitamin B2 deficiency.
It is involved in cellular energy metabolism through its conversion into FMN and FAD, which function as cofactors for numerous oxidation-reduction enzymes.
Riboflavin is also used in pharmaceutical and nutritional formulations, vitamin preparations and other products requiring a defined source of vitamin B2.
Riboflavin has established USP and Ph. Eur./BP quality-control requirements.
Important analytical tests include:
The USP specification gives an assay range of 98.0–102.0% on the dried basis, loss on drying NMT 1.5%, residue on ignition NMT 0.3%, and specific rotation −115° to −135°. The USP lumiflavin test has an absorbance acceptance criterion of NMT 0.025 at 440 nm.
The Ph. Eur./BP specification gives 97.0–103.0% on the dried substance, loss on drying NMT 1.5%, sulfated ash NMT 0.1%, and specific optical rotation −115° to −135°.
Riboflavin API is a well-established vitamin active ingredient with recognized USP and European Pharmacopoeia quality standards. Pharmaceutical-grade Riboflavin manufacturing requires controlled production, purification and analytical testing to ensure compliance with the applicable pharmacopoeial specification.
Quality control should address assay, identification, optical rotation, moisture, residue/ash, lumiflavin and related substances, together with applicable microbiological and elemental-impurity controls.
Riboflavin should be protected from light and excessive environmental exposure. USP specifies preservation in tight, light-resistant containers.
Riboflavin solutions are particularly susceptible to light-induced degradation, so appropriate light protection is important during handling and formulation.
Typical documentation can include:
| Parameter | Specification |
|---|---|
| Appearance | white to off-white crystalline powder |
| Identification | IR & HPLC compliant |
| Assay (HPLC) | 98.0% – 102.0% |
| Loss on Drying | NMT 1.5% |
| Residue on Ignition | NMT 0.3% |
| Specific Rotation | −115° to −135° |
| Melting Point | Approximately 290°C, with decomposition |