Equilibrium studies of the binary and ternary complexes involving tetracycline and amino acid or DNA constituents

The acid-base equilibria of tetracycline and its copper(II) complex formati on equilibria are investigated in dioxane-water mixtures. The ternary compl exes of copper(II) with tetracycline as primary ligand and amino acid or DN A constituent as secondary ligand are studied in 50% dioxane-water solution . The formation constants of the ternary and binary complexes with amino ac ids or DNA constituents are determined. The concentration distribution of t he various complex species are evaluated. Probable mode of chelation with t etracycline and DNA constituents is discussed. (C) 1999 Elsevier Science B. V. All rights reserved.