Riboflavin Tablets
DEFINITION
Riboflavin Tablets contains NLT 95.0% and NMT 115.0% of the labeled amount of riboflavin (C17H20N4O6).
ASSAY
•  Riboflavin Assay 481
Assay preparation:  Transfer a portion of the powder from NLT 20 finely powdered Tablets, equivalent to 20 mg of riboflavin, to a 250-mL flask, and add 150 mL of 0.1 N hydrochloric acid. Shake vigorously, and wash down the sides of the flask with sufficient 0.1 N hydrochloric acid to ensure that the pH remains below 1.5 during the subsequent period of heating. Heat the mixture on a steam bath, with frequent agitation, until the riboflavin has dissolved, or in an autoclave at 121 for 30 min. Cool, and with vigorous agitation, adjust the mixture with 1 N sodium hydroxide to a pH of 5–6. Transfer to a 1000-mL volumetric flask, and dilute with water to volume. If the solution is not clear, filter through paper known not to adsorb riboflavin. Dilute an aliquot of the clear solution with water to a final volume that contains 0.1 µg/mL of riboflavin.
Analysis:  Proceed as directed in the chapter.
Calculate the percentage of the labeled amount of riboflavin (C17H20N4O6) in the portion of Tablets taken:
Result = (IU/IS) × (CS/CU) × 100
IU== corrected fluorescence value from the Assay preparation
IS== corrected fluorescence value from the Standard Preparation
CS== concentration of USP Riboflavin RS in the Standard Preparation (µg/mL)
CU== nominal concentration of riboflavin in the Assay preparation (µg/mL)
Acceptance criteria:  95.0%–115.0%
PERFORMANCE TESTS
•  Dissolution 711
Medium:  Water; 900 mL
Apparatus 2:  50 rpm
Time:  45 min
Standard solution:  Known concentration of USP Riboflavin RS in Medium
Sample solution:  Filtered portion of the solution under test, suitably diluted with the Medium if necessary
Mobile phase:  A mixture of methanol, glacial acetic acid, and water (27:1:73) containing 1.40 mg/mL of sodium 1-hexanesulfonate
Chromatographic system 
Mode:  LC
Detector:  UV 280 nm
Column:  3.9-mm × 30-cm; packing L1
Flow rate:  1 mL/min
Injection size:  10 µL
System suitability 
Sample:  Standard solution
Suitability requirements 
Relative standard deviation:  NMT 3.0%
Analysis 
Samples:  Standard solution and Sample solution
Calculate the percentage of the labeled amount of riboflavin (C17H20N4O6) dissolved:
Result = (rU/rS) × (CS × D × V/L) × 100
rU== peak area of riboflavin from the Sample solution
rS== peak area of riboflavin from the Standard solution
CS== concentration of USP Riboflavin RS in the Standard solution (mg/mL)
D== dilution factor for the Sample solution
V== volume of Medium, 900 mL
L== label claim (mg/Tablet)
Tolerances:  NLT 75% (Q) of the labeled amount of riboflavin (C17H20N4O6) is dissolved.
•  Uniformity of Dosage Units 905: Meet the requirements
ADDITIONAL REQUIREMENTS
•  Packaging and Storage: Preserve in tight, light-resistant containers.
•  USP Reference Standards 11
USP Riboflavin RS Click to View Structure
Auxiliary Information— Please check for your question in the FAQs before contacting USP.
Topic/Question Contact Expert Committee
Monograph Natalia Davydova
Scientific Liaison
1-301-816-8328
(DS2010) Monographs - Dietary Supplements
711 Margareth R.C. Marques, Ph.D.
Senior Scientific Liaison
1-301-816-8106
(GCDF2010) General Chapters - Dosage Forms
Reference Standards RS Technical Services
1-301-816-8129
rstech@usp.org
USP35–NF30 Page 4547