Ethylenediammonium-Dicarboxylate Salts and Co-Crystallization for Biological and Pharmaceutical Applications

Abstract

Several ammonium type salts and co-crystals have been used in drug formulations to increase or decrease solubility, to improve stability, toxicity and also reducing the hygroscopicity of the products. Basically, a wide range of chemically diverse acidsand bases with different pKa, solubilities , molecular weight and other properties have been used for the purpose for a very long timein both drug and food formulations. In the present study, six ethylenediamminium salts containing thiocyanate and the anion derivedfrom diprotic acids namely oxalic (I), adipic (2), fumaric(3), succinic (4), azelaic (5) and sebacic (6) respectively, have been synthesized and characterized including their molecular structures. The difference in the pKa values of the acids unable the salt formation to be generalized. The molar conductivities of the salts are between 218 and 453 ohm-1cm2mol-1 with maximum value of 453 for salt (I). All the salts showed low activity against some selected bacteria and fungi and low toxicity against vero cell. The molecular structure of the salts will be presented and the biological activity will be compared with other ammonium salts.