Nicotinamide - Niacinamide

Pharmacology Niacin, vitamin B3, is the common name for nicotinic acid and niacinamide (nicotinamide). Nicotinic acid is present in the body as its active form, nicotinamide (niacinamide). 

Nicotinamide(niacinamide) adenine dinucleotide, NAD+, and the flavin mono- and di- nucleotides (FMN, FAD) exist in oxidized and reduced forms. This makes them invaluable cofactors in enzymatically catalyzed oxidation-reduction reactions. 

I. Pharmacology. Nicotinamide (niacinamide, vitamin Bg), one of the B vitamins, is required for the functioning of the coenzymes nicotinamide adenine dinucleotide (NAD) and nicotinamide adenine dinucleotide phosphate (NADP). NAD and NADP are responsible for energy transfer reactions. Niacin deficiency, which results in pellagra, can be corrected with nicotinamide. 

As with most other vitamins, the most inexpensive source of niacin is the synthetic source. Nicotinamide (niacinamide), the form usually taken as a vitamin supplement, is available in most food stores and pharmacies at a very reasonable cost. 

Nicotinamide, niacinamide, pellagra-preventive factor, is a relatively simple compound (pyridine 3-carboxylic amide, formula in Chapt. VI-4). In the mammalian organism, includii man, it can arise from tryptophan (cf. Chapt. VIII-11). Deficitencies, therefore, develop only under very special circumstances. 

Preformed niacin occurs in foods either as nicotinamide (niacinamide) or as the pyridine nucleotide coenzymes derived from it, or as nicotinic acid, without the amide nitrogen, which is the form known as niacin in North America. Both nicotinamide and nicotinic acid are equally effective as the vitamin, but in large doses they exert markedly different pharmacological effects, so it is important, at least in that context, to make and maintain the distinction. In addition to the preformed vitamin, an important in vivo precursor is the amino acid L-tryptophan, obtained from dietary protein. Because the human total niacin supply, and hence niacin status, depends on the dietary tryptophan supply as well as on the amount of preformed dietary niacin and its bioavailability, it has become the accepted practice to express niacin intakes as niacin equivalents, ... 

U.S. manufacturers of niacin and niacinamide include Nepera, Inc. and Reilly Industries, Inc. U.S. suppliers include BASF Corporation, Hoffmann-La Roche Inc., and Rhc ne-Poulenc. Western European producers and suppHers include Degussa, Rhc ne-Poulenc, BASF, Hoffmann-La Roche, and Lon2a (71). In 1995, the prices for niacin and nicotinamide were 9.75/kg and 9.25/kg, respectively (72,73). 

Pharmacology Niacinamide is synonymous with nicotinamide, 3-pyridine carboxamide, and nicotinic acid amide. Niacinamide is the amide of nicotinic acid (niacin, vitamin B3). Although nicotinic acid and nicotinamide function identically as vitamins, their pharmacologic effects differ. Nicotinamide does not have the hypolipidemic or vasodilating effects characteristic of niacin (nicotinic acid). 

Drugs that can increase carbamazepine serum levels include cimetidine, danazol, diltiazem, erythromycin, felbamate, clarithromycin, fluoxetine, isoniazid, niacinamide, propoxyphene, ketaconazole, itraconazole, verapamil, valproate, troleandomycin, loratadine, nicotinamide, tricyclic antidepressants, SSRIs, nefazodone, protease inhibitors. 

The determination of vitamins in pharmaceutical preparations continues to receive considerable attention. The voltammetric oxidation of vitamin A at a carbon paste electrode in the presence of vitamin E, a potential source of error in the assay, has been described [142,143]. Other assays involve the polaro-graphic determination of niacinamide [144-146], menadione (vitamin K3) [147], riboflavin (vitamin B2) [148], thiamine, riboflavin, and nicotinamide in multivitamin preparations [149], and multivitamins [150]. 

Common Name Aminicotin Niacinamide Nicosylamide Nicotilamid(e) Nicotinamide Nicotinsaureamid Nikotinsaureamid Vitamin B3 Vitamin PP Vitaminum pellagrapraeventivum Witamina PP... 

Nicotinic acid (melting point 236°C, density 1.473) and nicotinamide (melting point 129°C, density 1.400) are known as niacin and niacinamide in the food industry. Niacin is the most stable of all vitamins and is essential to humans and animals for growth and health. Niacin and niacinamide are nutritionally equivalent, and compete with one another. 

Scheme 20.4 Ammoxidation of 3-picoline and hydrolysis of cyanopyridine to niacinamide (nicotinamide) and niacin (nicotinic acid). Adapted from [106].

Niacinamide, U5P. Niacinamide, nicotinamide, nicotinic acid amide, is prepared by the amidation of esters of nicotinic acid or by pa.ssing ammonia gas into nicotinic acid at 320°C. Nicotinamide is a white cry.stalline powder that is odorless, or nearly so, and bitter. One gram is soluble in about I mL of water, I.S mL of alcohol, and about 10 mL of glycerin. Aqueous solutions aie neutral to litmus. For occurrence, action, and uses, see nicotinic acid. Niacinamide has pK values of O.. and 3.35. 

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