Nicotinamide-d₄is intended for use as an internal standard for the quantification of nicotinamide by GC- or LC-MS. Nicotinamide is an amide form of niacin, which is also known as vitamin B₃, that can be biosynthesizedin vivoor obtained through the diet.¹It is a precursor in the synthesis of the metabolic cofactor NAD⁺and an inhibitor of sirtuin 1 (SIRT1; IC₅₀=<50 µm).²Nicotinamide (10 µM) increases the activity of serine palmitoyltransferase (SPT) and the biosynthesis of ceramide, glucosylceramide, sphingomyelin, free fatty acids, and cholesterol in primary human keratinocytes.³Nicotinamide (40 µM) induces apoptosis in SNU-398, SNU-739, and HepG2 hepatocellular carcinoma (HCC) cells, and it prevents the formation of neoplastic lesions in a diethylnitrosamine-induced mouse model of HCC.⁴Unlike niacin, nicotinamide does not reduce plasma lipid levels or induce flushing.^5,6,7

1.Li, F., Chong, Z.Z., and Maiese, K.Cell life versus cell longevity: The mysteries surrounding the NAD+ precursor nicotinamideCurr. Med. Chem.13(8)883-895(2006) 2.Bitterman, K.J., Anderson, R.M., Cohen, H.Y., et al.Inhibition of silencing and accelerated aging by nicotinamide, a putative negative regulator of yeast sir2 and human SIRT1J. Biol. Chem.277(47)45099-45107(2002) 3.Tanno, O., Ota, Y., Kitamura, N., et al.Nicotinamide increases biosynthesis of ceramides as well as other stratum corneum lipids to improve the epidermal permeability barrierBr. J. Dermatol.143(3)524-531(2000) 4.Park, S.Y., Lee, K.B., Lee, M.-J., et al.Nicotinamide inhibits the early stage of carcinogen-induced hepatocarcinogenesis in mice and suppresses human hepatocellular carcinoma cell growthJ. Cell. Physiol.227(3)899-908(2012) 5.Lukasova, M., Hanson, J., Tunaru, S., et al.Nicotinic acid (niacin): New lipid-independent mechanisms of action and therapeutic potentialsTrends Pharmacol. Sci.32(12)700-707(2011) 6.Bodor, E.T., and Offermanns, S.Nicotinic acid: An old drug with a promising futureBr. J. Pharmacol.153(Suppl 1)S68-S75(2008) 7.Haining, C.G.Effects of anti-rheumatic compounds and pyridine derivatives on the cutaneous response to thurfyl nicotinate in the guinea-pigBr. J. Pharmacol. Chemother.21(1)104-112(1963)