固体状態におけるカフェインと数種の脂肪族有機二塩基酸との相互作用

概要

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The formation of solid complex of caffeine and aliphatic organic dibasic acid was tried in aqueous solution. Consequently, solid complexes were formed out of caffeine with oxalic acid, maleic acid and malonic acid at a molar ratio of 2 : 1,and with glutamic acid at a ratio of 1 : 1. However, no solid complexes with succinic acid and adipic acid were formed. The smaller the pK_a of organic dibasic acids, the easier the formation of solid complexes was. Although the pK_2 of glutamic acid was larger than that of succinic acid, the attempt to form solid complex with succinic acid was successful, probably because of the fact that the solubility of glutamic acid against water was much larger than that of succinic acid. The type of bonding of caffeine with organic dibasic acid was considered to be an intermolecular hydrogen bond between-COOH of organic acid and nitrogen at the 9-position of caffeine. With a decrease in pK_2,organic acid had a tendency to be stabilized thermally by the formation of its solid complex and its heat of reaction to form solid complex from crystals of its component also increased.
公益社団法人日本薬学会の論文
1980-07-25