Metal -Chelator Therapy : Stability Constants of Transition Metal Complexes of Pyrimidine and Sulphonamide DrugsAuthor(s): Adedibu C. Tella and Joshua A. Obaleye
Stability constant of metal complexes of pyrimidine and sulphonamides drugs were determined using spectrophotometric method. Stability constants of the complexes were determined at 25o C. Ionic strength was maintained constant using 0.1M KNO3. .Stoichometry of the complexes by Job’ s method showed that metal-drug ratio is 1 : 2. For the metal salts, the order of stability constant (β) was found to be Cu (II) > Fe (III) > Ni (II) > Co (II) > Zn (II) in accordance with lrving- Williams series. The overall stability constants (β) were found to be log 10.68, 5.5 and 4.8 for trimethoprim, sulphadiazine and sulphadimidine, respectively. The order of stability constant follows this trend: Trimethoprim > Sulphadiazine > Sulphadimidine. The stability constant data revealed that this ligand may be used as antidote or chelating agent for medical treatment of metals overload or poisoning.