SPECTROSCOPIC methods such as mass, infrared, nuclear magnetic resonance and X-ray diffraction in combination with thermal measurements are used to monitor and describe the physicochemical properties of the solid drug substances; the novel nor- and ciprofloxacin chromium(III) and zirconium (IV) metal complexes. The results support the formation of complexes with the formula [Cr(Nor)2](NO3)3.4 H2O, [Cr (Cip)2].7H2O, [Zr (Nor)2].3.5 H2O and [Zr (Cip)2].5H2O. The FT/IR spectra of the isolated complexes suggest that norfloxacin and ciprofloxacin act as bidentate ligands through the ring carbonyl oxygen atom and one of the oxygen atoms of the carboxylic group. Thermal studies indicate that the complexes dehydrate at lower temperatures followed by pyrolytic decomposition at higher temperatures and the results show that zirconium complexes are more stable than chromium complexes.