THERMODYNAMIC STUDIES OF METAL COMPLEXES OF TETRACYCLINE AND ITS APPLICATION IN DRUG ANALYSIS

摘要

The complexation reactions between Fe3+, Cu2+ and Pd2+ ions with tetracycline HCl (TC) in water or DMF were studied by the spectrophotometric methods at [(15, 25, 35 and 45 +/- 0.1) degrees C]. The complexation process was optimized in terms of pH, temperature and time. The stoichiometry of the complexes (metal ion/ligand) were found to be 1:2 [for Pd(II)-TC and Fe(III)-TC] and 1:1 [for Cu(II)-TC]. The formation constants of the resulting complexes were determined from computer fitting absorbance-mole ratio data and emphasized by the KINFIT program. The values of the thermodynamic parameters for complexation reactions were obtained from the temperature dependence of the stability constants. Tetracycline could be determined by measuring the absorbance of each complex at its specific lambda(max).