Biological Study of Schiff Base Metal Complexes Derived from Drugs

The work presented concerns the preparation, characterization and biological evaluation of Cu(II) and Zn(II) complexes of Schiff bases derived from amoxycillin, cephalexin, sulphamethoxazole and trimethoprim, and salicylalde-hyde and pyridoxal. In these complexes an amino group available in the drug substances was allowed to react with salicylaldehyde and pyridoxal hydrochloride, separately, to obtain Schiff bases which were, subsequently, reacted with Cu(CH3COO)2. H2O and/or Zn(CH3COO)2.2H2O to form Schiff base metal complexes. The ligands and the complexes were characterized by microanalytical, thermogravimetric, magnetic and spectroscopic data. The geometry of the Zn(II) complexes appears to be simple square-pyramidal or octahedral. All the compounds under investigation possess antibacterial activity. The antibacterial activity showed the following trend: Cu(II)-complexes > Zn(II)-complexes > Schiff base ligands > parent xxvi drugs. The Cu(II)-complexes with the Schiff bases derived from cephalexin showed substantially enhanced activity against P. aeruginosa as compared with the parent drug.