Chowhan Z T
J Pharm Sci. 1978 Sep;67(9):1257-60. doi: 10.1002/jps.2600670918.
The solubilities of naproxen, 7-methylsulfinyl-2-xanthonecarboxylic acid, 7-methylthio-2-xanthonecarboxylic acid, and their sodium, potassium, calcium, and magnesium salts were determined as a function of pH. The results on the solubility of naproxen and its salts were in excellent agreement with the theoretical profiles describing the relationship between pH values of the solutions and the dissociation constant of the acid. The solubilities of the two xanthonecarboxylic acids were higher at higher pH values than the values calculated when complete dissociation in solution was assumed. The influence of the salt species on the solubility of organic carboxylic acids, at and above pH values of complete ionization, cannot be predicted even qualitatively from equations used for alkali and alkaline earth metal salts.
测定了萘普生、7-甲基亚磺酰基-2-呫吨羧酸、7-甲硫基-2-呫吨羧酸及其钠盐、钾盐、钙盐和镁盐的溶解度与pH的关系。萘普生及其盐类溶解度的结果与描述溶液pH值和酸解离常数之间关系的理论曲线非常吻合。两种呫吨羧酸在较高pH值下的溶解度高于假设其在溶液中完全解离时计算出的值。即使从用于碱金属和碱土金属盐的方程式中，也无法定性地预测盐种类对完全电离pH值及以上的有机羧酸溶解度的影响。
