Chelating tendencies of some sulpha drugs

The acid dissociation constant of sulfadiazine, sulfamerazine and sulfasomidine in 50% ethanolic solution were determined by pH-metric titration at temperature 30C and in different ionic strength. Also, their formation constants with Cu[II], Zn[II], Ni[II], Co[II], Mn[II] have been studied. The free energies of the complexes formed were deduced and the relation between the stabilities of these complexes and the ionization potenital of the cautions were discussed