Abstract
Stability constant of some transition metals like Mn(II), Co(II), Ni(II), Cu(II) and Zn(II) complexes with pyrazinamide, isoniazid and ethambutol-HCl (22'-(1,2-Ethane dihydiimino)-bis-1-butanol) etb, an antibacterial drugs have been evaluated at 30 degrees C & fixed 0.1 M (NaClO4) ionic strength in aqueous medium pH metrically. Proton ligand stability constants & metal ligand stability constants were determined by using Calvin Bjerrum titration technique as modified by Irving & Rossoti. Stability constants were discussed in terms of order of stability, basicity of ligands & correlated with atomic number, ionization potential, electronegativity and reciprocal of ionic radii.