Thermal, spectroscopic and antimicrobial activity characterization of some norfloxacin complexes

Abstract

Coordination compounds of transition metals with norfloxacin (Nor) have potential to improve its effectiveness, as already discussed for some compounds found in the literature. The complexes in the solid state were prepared by precipitation of the respective metal cation (M = Mn(II), Co(II), Ni(II), Cu(II) and Zn(II)) with a norfloxacin sodium salt solution. The thermal behavior under oxidative and pyrolysis conditions was investigated employing thermogravimetry and differential thermal analysis (TG/DTG-DTA) and evolved gas analysis (EGA/TG-FTIR), and the complexes were characterized by elemental analysis (EA), EDTA complexometric titration, infrared spectroscopy (FTIR) and X-ray powder diffraction (XRD). By these results, the minimum formula was established as [M(Nor) 2 (H 2 O) 2 ]ÁnH 2 O, where n = 3 (Ni), 2.5 (Mn Co, Zn), or 2 (Cu). The evolved gases identified during thermal decomposition of Ni and Cu complexes were ethylene, CO 2 and CO for Ni; CO 2 and ethane for Cu. Also, antimicrobial activity of the complexes was evaluated by in vitro susceptibility test using the agar diffusion method, and the results were compared with the uncomplexed molecule. It was found that norfloxacin complexation modifies its antibacterial activity. The activity depends on the type of metal ion and microorganism; Mn(II), Co(II) and Zn(II) complexes significantly increased activity against the tested gram-negative bacteria.

Investigation of Drug–Polymer Miscibility, Molecular Interaction, and Their Effects on the Physical Stabilities and Dissolution Behaviors of Norfloxacin Amorphous Solid Dispersions

“…Figure shows the heating curves for pure drug and drug/polymer mixtures as a function of varying fractions at the heating rate of 10 °C/min. The onset melting temperature of crystalline NFX is 220.60 °C, which is in good agreement with the published literature . Clear evidence of the melting depression can be seen in all three systems that upon increasing the polymer fraction in the physical mixtures, the onset temperature and the heat of fusion were gradually reduced.…”

“…The onset melting temperature of crystalline NFX is 220.60 °C, which is in good agreement with the published literature. 34 Clear evidence of the melting depression can be seen in all three systems that upon increasing the polymer fraction in the physical mixtures, the onset temperature and the heat of fusion were gradually reduced. This phenomenon is indicative of a certain degree of mixing at the melting temperature.…”

“…The interaction parameters of 0.4558, −1.5721, and −3.1767 were obtained for NFX/PVP, NFX/ HPMC, and NFX/HPMCP, respectively. As a greater absolute value of slope suggests the higher drug−polymer miscibility, 34 the rank order of miscibility of NFX/polymers should be NFX/HPMC > NFX/HPMCP > NFX/PVP. Thus, the drug−polymer miscibility has been qualitatively and quantitatively evaluated through the measurement of Hansen's solubility parameter and F−H interaction parameter, whose results reveal that the effectiveness of polymers to form miscible system with NFX would be HPMCP > HPMC > PVP.…”

“…The interaction parameters of 0.4558, −1.5721, and −3.1767 were obtained for NFX/PVP, NFX/HPMC, and NFX/HPMCP, respectively. As a greater absolute value of slope suggests the higher drug–polymer miscibility, the rank order of miscibility of NFX/polymers should be NFX/HPMC > NFX/HPMCP > NFX/PVP.…”

A perception into binary and ternary copper (II) complexes: synthesis, characterization, DFT modeling, antimicrobial activity, protein binding screen, and amino acid interaction

“…To avoid the problem of misuse of these antibiotics, the complexation of fluoroquinolones with transition and non-transition metal ions was used as an alternative to conventional drugs [ 7 – 11 ]. However, the combinations of metal with pharmaceuticals expand the activity of the drug, reduce their toxicity, improve the ability to act as regulators of gene expression and serve as microbiological tools [ 12 – 15 ].…”