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C6H5NO2 123.11

3-Pyridinecarboxylic acid.
Nicotinic acid [59-67-6].
» Niacin contains not less than 99.0 percent and not more than 101.0 percent of C6H5NO2, calculated on the dried basis.
Packaging and storage— Preserve in well-closed containers.
B: Ultraviolet Absorption 197U
Solution: 20 µg per mL.
Medium: Use the Buffer solution, prepared as directed in the Assay.
Ratio: A237 / A262, between 0.46 and 0.50.
Loss on drying 731 Dry it at 105 for 1 hour: it loses not more than 1.0% of its weight.
Residue on ignition 281: not more than 0.1%.
Chloride 221 A 0.50-g portion shows no more chloride than corresponds to 0.15 mL of 0.020 N hydrochloric acid (0.02%).
Sulfate 221 A 0.50-g portion shows no more sulfate than corresponds to 0.10 mL of 0.020 N sulfuric acid (0.02%).
Heavy metals, Method I 231 Mix 1 g with 4 mL of 1 N acetic acid, dilute with water to 25 mL, heat gently until solution is complete, and cool: the limit is 0.002%.
Ordinary impurities 466
Test solution: water.
Standard solution: water.
Eluant: a mixture of methanol and 0.1 N hydrochloric acid (9:1).
Visualization: 1.
Buffer solution— Dissolve 6.8 g of monobasic potassium phosphate in 1 L of water. Adjust with 50% sodium hydroxide solution to a pH of 7.0.
Assay preparation— Transfer about 200 mg of Niacin, accurately weighed, to a 500-mL volumetric flask; add the Buffer solution to dissolve; dilute with the Buffer solution to volume; and mix. Transfer 5.0 mL of this solution to a 100-mL volumetric flask, dilute with the Buffer solution to volume, and mix.
Procedure— Concomitantly determine the absorbances of the Assay preparation and a solution of USP Niacin RS in the same medium (Standard preparation), at a concentration of about 20 µg per mL, in 1-cm cells at the wavelength of maximum absorbance at about 262 nm, with a suitable spectrophotometer, using the Buffer solution as the blank. Calculate the quantity, in mg, of C6H5NO2 in the portion of Niacin taken by the formula:
10C(AU / AS)
in which C is the concentration, in µg per mL, of USP Niacin RS in the Standard preparation; and AU and AS are the absorbances of the solution of the Assay preparation and the Standard preparation, respectively.
Auxiliary Information— Please check for your question in the FAQs before contacting USP.
Topic/Question Contact Expert Committee
Monograph Curtis Phinney

(DSN05) Dietary Supplements - Non-Botanicals
Reference Standards Lili Wang, Technical Services Scientist
USP32–NF27 Page 3076
Pharmacopeial Forum: Volume No. 29(6) Page 1937
Chromatographic Column—
Chromatographic columns text is not derived from, and not part of, USP 32 or NF 27.