Niacin
;)
3-Pyridinecarboxylic acid.
Nicotinic acid [59-67-6].
»Niacin contains not less than 99.0percent and not more than 101.0percent of C6H5NO2,calculated on the dried basis.
Packaging and storage—
Preserve in well-closed containers.
Identification—
A:Infrared Absorption á197Mñ.
B:Ultraviolet Absorption á197Uñ—
Solution:
20µg per mL.
Medium:
Use the Buffer solution,prepared as directed in the Assay.
Ratio:
A237/A262,between 0.46and 0.50.
Loss on drying á731ñ—
Dry it at 105
for 1hour:it loses not more than 1.0%of its weight.
for 1hour:it loses not more than 1.0%of its weight.
Residue on ignition á281ñ:
not more than 0.1%.
Chloride á221ñ—
A0.50-g portion shows no more chloride than corresponds to 0.15mLof 0.020Nhydrochloric acid (0.02%).
Sulfate á221ñ—
A0.50-g portion shows no more sulfate than corresponds to 0.10mLof 0.020Nsulfuric acid (0.02%).
Heavy metals,Method Iá231ñ—
Mix 1g with 4mLof 1Nacetic acid,dilute with water to 25mL,heat gently until solution is complete,and cool:the limit is 0.002%.
Ordinary impurities á466ñ—
Test solution:
water.
Standard solution:
water.
Eluant:
a mixture of methanol and 0.1Nhydrochloric acid (9:1).
Visualization:
1.
Organic volatile impurities,Method IVá467ñ:
meets the requirements.
Assay—
Buffer solution—
Dissolve 6.8g of monobasic potassium phosphate in 1Lof water.Adjust with 50%sodium hydroxide solution to a pHof 7.0.
Assay preparation—
Transfer about 200mg of Niacin,accurately weighed,to a 500-mLvolumetric flask;add the Buffer solutionto dissolve;dilute with the Buffer solutionto volume;and mix.Transfer 5.0mLof this solution to a 100-mLvolumetric flask,dilute with the Buffer solutionto volume,and mix.
Procedure—
Concomitantly determine the absorbances of the Assay preparationand a solution of USP Niacin RSin the same medium (Standard preparation),at a concentration of about 20µg per mL,in 1-cm cells at the wavelength of maximum absorbance at about 262nm,with a suitable spectrophotometer,using the Buffer solutionas the blank.Calculate the quantity,in mg,of C6H5NO2in the portion of Niacin taken by the formula:
10C(AU/AS),
in which Cis the concentration,in µg per mL,of USP Niacin RSin the Standard preparation;and AUand ASare the absorbances of the solution of the Assay preparationand the Standard preparation,respectively.
Auxiliary Information—
Staff Liaison:Lawrence Evans,III,Ph.D.,Scientist
Expert Committee:(DSN)Dietary Supplements:Non-Botanicals
USP28–NF23Page 1368
Pharmacopeial Forum:Volume No.29(6)Page 1937
Phone Number:1-301-816-8389