»Niacinamide contains not less than 98.5percent and not more than 101.5percent of C6H6N2O,calculated on the dried basis.
Packaging and storage Preserve in tight containers.
A: Infrared Absorption á197Kñ.
Solution: 20µg per mL.
Ratio: A245/A262,between 0.63and 0.67.
Melting range á741ñ: between 128and 131.
Loss on drying á731ñ Dry it over silica gel for 4hours:it loses not more than 0.5%of its weight.
Residue on ignition á281ñ: not more than 0.1%.
Heavy metals,Method IIá231ñ: 0.003%.
Readily carbonizable substances á271ñ Dissolve 200mg in 5mLof sulfuric acid TS:the solution has no more color than Matching Fluid A.
Organic volatile impurities,Method Iá467ñ: meets the requirements.
Mobile phase Prepare a filtered and degassed solution containing 0.005Msodium 1-heptanesulfonate and methanol (70:30).
Standard preparation Transfer about 50mg of USP Niacinamide RS,accurately weighed,to a 100-mLvolumetric flask,dissolve in about 3mLof water,dilute with Mobile phaseto volume,and mix.Dilute 4.0mLof the resulting solution with Mobile phaseto 50.0mL,and mix.
Resolution solution Prepare a solution containing equal volumes of the Standard preparationand of a niacin solution similarly prepared and having the same concentration.
Assay preparation Prepare as directed under Standard preparation,using Niacinamide instead of the Reference Standard.
Chromatographic system (see Chromatography á621ñ)The liquid chromatograph is equipped with a 254-nm detector and a 3.9-mm ×30-cm column containing packing L1.The flow rate is about 2mLper minute.Chromatograph the Resolution solution:the resolution,R,between the niacin and niacinamide peaks is not less than 3.0.Chromatograph replicate injections of the Standard preparation,and record the peak responses as directed for Procedure:the relative standard deviation is not more than 2.0%.
Procedure Separately inject equal volumes (about 20µL)of the Standard preparationand the Assay preparationinto the chromatograph,record the chromatograms,and measure the responses for the major peaks.Calculate the quantity,in mg,of C6H6N2Oin the portion of Niacinamide taken by the formula:
1250C(rU/rS),in which Cis the concentration,in mg per mL,of USP Niacinamide RSin the Standard preparation,and rUand rSare the peak responses for the Assay preparationand the Standard preparation,respectively.
Auxiliary Information Staff Liaison:Lawrence Evans,III,Ph.D.,Scientist
Expert Committee:(DSN)Dietary Supplements:Non-Botanicals