Silver complexes ascorbic acid

The deposition of silver in tissues is the result of the precipitation of insoluble silver salts, such as silver chloride and silver phosphate. These insoluble silver salts appear to be transformed into soluble silver sulfide albuminates, to bind to or form complexes with amino or carboxyl groups in RNA, DNA, and proteins, or to be reduced to metallic silver by ascorbic acid or catecholamines (Danscher 1981). The blue or gray discoloration of skin exposed to ultraviolet light in humans with argyria may be caused by the photoreduction of silver chloride to metallic silver. The metallic silver is then oxidized by tissue and bound as black silver sulfide (Danscher 1981). Bucklet et al. (1965) identified silver particles deposited in the dermis of a woman with localized argyria as being composed of silver sulfide. 

Water-soluble vitamins in formulations have been determined by use of ion-pair chromatography. The vitamins include several B vitamins as well as niacin, folic acid, and ascorbic acid (565). Vitamins D and Da were rapidly separated on reverse phase columns (247) as are vitamins A, D, and E in multivitamin tablets (564). Addition of silver ions to the mobile phase has been shown to increase the flexibility inherent in RPC by complexing with the unsaturated bonds and thereby decreasing the retention factor. This effect is also observed with other unsaturated drug molecules including steroids (247). Vitamin A and related compounds have... 

Development modifiers alter the rate of development (development accelerators or inhibitors) or may render silver halide grains developable. Certain complexes of ruthenium, in particular [Ru(NH3)6]Cl3, are accelerators of development with hydroquinones and ascorbic acid.46 Several complex ions of cobalt, for example [Co(NH3)5OH2]3+, [CoC1(NH3)5]2+ and [Co(en)3]3+, are development accelerators.47... 

The images recorded were compared the results on reduction of silver ions by ascorbic acid (Fig. 3). The similarity of shape and size of silver nanoparticles produced from the above complex and with the external reducing agent is observed. 

There are only scant reports of the reaction of silver ions with aliphatic or aromatic hydroxy acids and only a few stability constants have been reported.264 In general only weak complexes were formed and typical examples include reactions with ascorbic or tartaric acids. 

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