Niacin
C6H5NO2 123.11
3-Pyridinecarboxylic acid;
Nicotinic acid
[59-67-6].
(nye' a sin).
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C6H5NO2 123.11
3-Pyridinecarboxylic acid;
Nicotinic acid
[59-67-6].DEFINITION
Niacin contains NLT 99.0% and NMT 101.0% of niacin (C6H5NO2), calculated on the dried basis.
IDENTIFICATION
• B. Ultraviolet Absorption 
197U
197U
Wavelength range:
200–300 nm
Sample solution:
20 µg/mL in Buffer solution, prepared as directed in the Assay
Acceptance criteria:
Meets the requirements in the chapter. The A237/A262 ratio is 0.46–0.50.
ASSAY
• Procedure
Buffer solution:
Dissolve 6.8 g of monobasic potassium phosphate in 1000 mL of water. Adjust with 50% sodium hydroxide solution to a pH of 7.0.
Standard solution:
0.02 mg/mL of USP Niacin RS in Buffer solution
Sample solution:
0.02 mg/mL of Niacin in Buffer solution
Blank:
Buffer solution
Instrumental conditions
Mode:
UV-Vis
Analytical wavelength:
262 nm
Cell:
1 cm
Analysis
Samples:
Standard solution, Sample solution, and Blank
Determine the absorbances of the solutions against the Blank.
Calculate the percentage of niacin (C6H5NO2) in the portion of Niacin taken:
Result = (AU/AS) × (CS/CU) × 100
| AU | = | = absorbance of the Sample solution |
| AS | = | = absorbance of the Standard solution |
| CS | = | = concentration of USP Niacin RS in the Standard solution (µg/mL) |
| CU | = | = concentration of Niacin in the Sample solution (µg/mL) |
Acceptance criteria:
99.0%–101.0% on the dried basis
IMPURITIES
• Residue on Ignition 281:
NMT 0.1%
281:
NMT 0.1%
• Chloride and Sulfate, Chloride 221
221
Standard:
0.15 mL of 0.020 N hydrochloric acid
Sample:
0.50 g of Niacin
Acceptance criteria:
NMT 0.02%
• Chloride and Sulfate, Sulfate 221
221
Standard:
0.10 mL of 0.020 N sulfuric acid
Sample:
0.50 g of Niacin
Acceptance criteria:
NMT 0.02%
• Heavy Metals, Method I 231
231
Test preparation:
Mix 1 g with 4 mL of 1 N acetic acid, and dilute with water to 25 mL. Heat gently until solution is complete, and cool.
Acceptance criteria:
NMT 20 ppm
• Ordinary Impurities 466
466
Standard solutions and Test solution:
Use water as the solvent.
Eluant:
A mixture of methanol and 0.1 N hydrochloric acid (9:1)
Visualization:
1
Analysis:
Proceed as directed in the chapter.
Acceptance criteria:
NMT 2.0% of total ordinary impurities
SPECIFIC TESTS
• Loss on Drying 731:
Dry a sample at 105
for 1 h: it loses NMT 1.0% of its weight.
731:
Dry a sample at 105 for 1 h: it loses NMT 1.0% of its weight.
ADDITIONAL REQUIREMENTS
• Packaging and Storage:
Preserve in well-closed containers.
• USP Reference Standards 11
11
USP Niacin RS 
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Auxiliary Information—
Please check for your question in the FAQs before contacting USP.
| Topic/Question | Contact | Expert Committee |
|---|---|---|
| Monograph | Huy T. Dinh, M.S.
Scientific Liaison 1-301-816-8594 |
(DS2010) Monographs - Dietary Supplements |
| Reference Standards | RS Technical Services 1-301-816-8129 rstech@usp.org |
USP35–NF30 Page 4042
Pharmacopeial Forum: Volume No. 29(6) Page 1937