Abstract
With the object of obtaining information about the behavior of aminophylline in aqueous medium, the mode of interaction between theophylline (TP) and ethylenediamine (ED) in water was studied. The molar ratio of the solubilizate-solubilizer complex was confirmed to be 1 : 1 by means of refractometry as well as phase diagram study, and stability constant of the complex was determined by solubility method. The comparative study of TP and structurally related compounds suggested that the soluble complex is united in such a way that ionic bonding between ionized imino and amino groups of TP and ED, respectively, is stabilized by hydrogen bonding between 6-keto group of TP and amino group of ED.
