Determination of Stability Constants of Enalaprilcomplexes With Some Metal Ions

Twelve metal ions viz; Fe (III), A1 (III), Cr (III), La (III), Y (III), Bi (III), Cu (II), Co (II), Ni (II), Mn (II), Pd (II) and Hg (II) were selected to elucidate the interaction of these metal ions with enalapril maleate using potentiometric method. The protonation constant of the ligand and stability constants of complexes formed have been tabulated with different three ionic strengths, I = 0.05, 0.1 and 0.15 M NaNO3 in aqueous solutions at 25°c± 0.1. Complexes of 1 : 1 , 1:2 and /or 1: 3 metal to ligand ratios are formed depending on the nature of the ligand or metal ions. The order of stability constants of the binary complexes were examined. As well as, the stiochiometry of the complexes confirmed by conductometric method