Niacinamid

Description of Method. The water-soluble vitamins Bi (thiamine hydrochloride), B2 (riboflavin), B3 (niacinamide), and Be (pyridoxine hydrochloride) may be determined by CZE using a pH 9 sodium tetraborate/sodlum dIhydrogen phosphate buffer or by MEKC using the same buffer with the addition of sodium dodecyl-sulfate. Detection Is by UV absorption at 200 nm. An Internal standard of o-ethoxybenzamide Is used to standardize the method. 

Cyanopyridines are usually manufactured from the corresponding picoline by catalytic, vapor-phase ammoxidation (eq. 7) in a fixed- or fluid-bed reactor (28). 3-Cyanopyridine (25) is the most important nitrile, as it undergoes partial or complete hydrolysis under basic conditions to give niacinamide... 

The relative production volumes of pyridine compounds can be ranked in the following order pyridine (1) > P-picoline (3) > a-picoline (2)> niacin (27) or niacinamide (26)> 2-vinylpyridine (23)> piperidine (18). U.S. and Japanese production was consumed internally as well as being exported, mainly to Europe. European production is mosdy consumed internally. Growth in production of total pyridine bases is expected to be small through the year 2000. 

Pyridine is also sold as a 1° grade, which means that the boiling poiat range of 98% of the sample will fall ia a 1°C range which iacludes the normal boiling poiat of (1) (115.3 0.1°C). Niacia (27) and niacinamide (26), equivalent forms of vitamin B, are generally sold under a US. Pharmacopeia (USP) specification (78). They are also sold as a feed-grade supplement (see Vitamins). 

Most of them are generally classified as poisons. Exceptions to this rule are known. A notable one is 4-dimethyl aminopyridine (DMAP) (24), which is widely used in industry as a superior acylation catalyst (27). Quaternary salts of pyridines are usually toxic, and in particular paraquat (20) exposure can have fatal consequences. Some chloropyridines, especially polychlorinated ones, should be handled with extra care because of their potential mutagenic effects. Vinylpyridines are corrosive to the skin, and can act as a sensitizer for some susceptible individuals. Niacin (27), niacinamide (26), and some pyridinecarbaldehydes can cause skin flushing. 

The Kixnig reaction (Fig. 5) has been used to determine the amount of nicotinic acid and niacinamide. In this procedure, quatemization of the pyridine nucleus by cyanogen bromide is followed by ring opening to generate the putative dialdehyde intermediate. Reaction of this compound with an appropriate base, such as p-rr ethyl am in oph en o1 sulfate (47) or sulfanilic acid (48), generates a dye. The concentration of this dye is deterrnined c olo rime trie ally. 

Specifications for niacin and niacinamide for food use are given in the Vood Chemicals Codex (63) and for pharmaceutical use in the United States Pharmacopeia (64). The Codex also gives specifications for niacinamide ascorbate. 

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). 

Hypervitaminosis A, 25 789 Hypervitaminosis biotin, 25 800 Hypervitaminosis cobalamin, 25 804 Hypervitaminosis D, 25 792 Hypervitaminosis E, 25 794 Hypervitaminosis folic acid, 25 803 Hypervitaminosis K, 25 795 Hypervitaminosis niacin, 25 798 Hypervitaminosis niacinamide, 25 798 Hypervitaminosis pantothenic acid, 25 799 Hypervitaminosis pyridoxine, 25 799 Hypervitaminosis riboflavin, 25 797 Hypervitaminosis thiamine, 25 796 Hyphenated techniques... 

The SP procedure of water-soluble vitamins from multivitamin tablets is particularly challenging due to the diverse analytes of varied hydrophobicities and pfC. Water-soluble vitamins (WSVs) include ascorbic acid (vitamin C), niacin, niacinamide, pyridoxine (vitamin B ), thiamine (vitamin Bj), folic acid, riboflavin (vitamin B2) and others. While most WSVs are highly water soluble, riboflavin is quite hydrophobic and insoluble in water. Folic acid is acidic while pyridoxine and thiamine are basic. In addition, ascorbic acid is light sensitive and easily oxidized. The extraction strategy employed was a two-step approach using mixed solvents of different polarity and acidity as follows ... 

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). 

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. 

Vitamins Niacin, niacinamide, pyridoxine, thiamine, and Hexanesulfonate MeOH-HtO (25 75) 1 Octadecyl ... 

Naphthaleneacetic acid, 296 Narrow bore columns, 33, 34 Natural products, analysis by RPC, 293 Neohesperidin dihydrochalcone, 295 Netilmicin, 282 Niacin, 260, 263, 296 Niacinamide, 263... 

Other amino acids, and some antibiotics, especially the conversion of 6-amino-penicillanic acid (APA) to 7-aminodesacetoxycephalosporanic acid (ADCA), acrylamide, aspartame, citric acid, and niacinamide. 

Byproducts of large industrial-scale processes are valorized for instance, in the DuPont process for adiponitrile, the byproduct a-methylglutaronitrile is upgraded to p-picoline and further to niacinamide. 

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