Abstract
Interaction of Mg(II) and Ca(II) alkaline earth metal ions with pyrazinamide(pyrazine carboxamide) pyr, isoniazid (isonicotinic acid hydrazide) iso and ethambutol-HCl (22'-1.2-ethane dihydiimino)-bis-1-butanol) etb an antibacterial drugs (anti tuberculosis drugs) have been investigated at 30 degrees C and 0.1 M fixed (NaClO(4)) ionic strength in aqueous medium potentiometrically. Proton ligand stability constants and metal ligand stability constants were calculated by using Calvin Bjerrum titration technique as modified by Irving and Rossoti. Stability constants were discussed in terms of order of stability, basicity of ligands and correlated with atomic number, ionization potential, electro negativity, and reciprocal-of ionic radii.