Solution studies on binary and ternary complexes of copper(II) with some fluoroquinolones and 1,10-phenanthroline: Antimicrobial activity of ternary metalloantibiotics

Article · May 2007with14 Reads
DOI: 10.1016/j.ijpharm.2006.10.035 · Source: PubMed
Interaction of norfloxacin and ofloxacin with copper(II) and copper(II)/phenanthroline has been studied in aqueous solution and the stability constants of the binary complexes Cu(II)/fluoroquinolone and of the ternary complexes Cu(II)/phenanthroline/fluoroquinolone have been determined by potentiometry and UV-vis spectrophotometry. The stability constants for the binary and ternary complexes of norfloxacin were always higher than those found for ofloxacin and comparing the values obtained for the binary and ternary species (DeltalogK) it is possible to conclude that the ternary complexes are more stable than the binary ones, suggesting that an interaction occurs between the ligands in the ternary complexes. From the distribution diagrams it is possible to state that at physiological pH 7.4, the copper ternary complexes, are the main species in solution not only at the concentration used to determined the stability constants but also at the minimum inhibitory concentration. The antibacterial activity of these complexes, in different bacterial strains, was determined, at physiological pH, and the results obtain show that these ternary complexes may be good candidates as metalloantibiotics.
    • Results of analysis were validated statistically and by recovery studies [19]. The spectrophotometric (UV and Vis) [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18]20,21],chromatographic (HPLC, GC and TLC) [9,19,22,23] and electrochemical (polarography, voltammetry and other) [24][25][26][27][28][29]methods most prevalentto identify different drugs in pure and pharmaceutical dosage forms.
    [Show abstract] [Hide abstract] ABSTRACT: UV-Vis spectroscopic method for the analysis of cefixime (CEFI)in pure form and pharmaceutical formations through complexation with Cu(II) using acetate-NaOH buffer in mixture water: methanol has been developed. Optimal temperature and time for coupling were established at 25±5°C with time ranging from 0 to10 min. The formation complex, CEFI: Cu(II) gives maximum absorbance of the yellow color occurred at λ= 410 nm and the molar absorptivity is 5. 12 x 103 L. mol-1. cm-1. The reaction between CEFI and Cu(II) occurred at a stoichiometric ratio of 1: 1. All reaction conditions have been optimized to obtain the complex. Under optimum conditions Beer's law was obeyed at concentrations ranging from 0. 2267 to 22. 671μg. mL-1 with correlation coefficients≥0. 9995 in all cases with RSD generally less than 4. 0%. The limit of detection (LOD) and limit of quantification (LOQ) was found to be 0. 030μg. mL-1 and 0. 091μg. mL-1, respectively. The proposed method was simple, economic, accurate and successfully applied to the determination of CEFI in pharmaceuticals with average recovery of 98. 00 to 103. 00%, the results obtained agree well with the contents stated on the labels.
    Full-text · Article · Jan 2013
    • of the two complexes was studied by microdilution method, and our results show that both complexes inhibited the growth of the E. coli bacteria very effectively [51][52][53][54][55]. e MIC values for both complexes were determined to be 12.5 í µí¼‡í µí¼‡g mL −1 .
    [Show abstract] [Hide abstract] ABSTRACT: Two new polypyridyl complexes [Ru(ttp)(L1)Cl]PF6 (1) and [Ru(ttp)(L2)Cl]PF6 (2) with noninnocent o-benzoquinonediimine (L1; bqdi) and 4,5-dimethyle-o-benzoquinonediimine (L2; 4,5-di-Mebqdi) ligands were synthesized and characterized (ttp = 4  -p-toloyle-2, 2  : 6  , 2   -terpyridine). Cyclic voltammetry studies suggest that noninnocent ligands are coordinated in their benzoquinonediimine form. Preliminary ruthenium complexes-induced DNA dysfunction was studied on E. coli GM109 DNA by means of melting temperature analysis (Tm). Our results suggest that complex (2) inhibited DNA function more strongly compared to (1). Antibacterial activities of the complexes against E. coli bacteria were studied, and Minimum inhibitory concentration (MIC) values were evaluated. Both complexes showed great antibacterial activities.
    Full-text · Article · Dec 2012
  • [Show abstract] [Hide abstract] ABSTRACT: In this study, a new binary complex [Cu(HCip)2](NO3)2 · 6H2O (1) has been synthesized and then characterized by X-ray structure analyses. In this compound, each ciprofloxacin acts as a bidentate ligand resulting in a crystallographically planar configuration; the nitrate anions are located in apical positions with an axial distance significantly larger than the equatorial distances, which would be consistent with a very weak metal ion interaction due to the Jahn–Teller effect. In addition, both the synthesis and characterization of two new ternary complexes of ciprofloxacin–copper(II)–1,10-phenanthroline, [Cu(phen)(Cip)](NO3) · 4H2O (2) and Cu(phen)(HCip)(NO3)2 · H2O (3), have been accomplished. We have also undertaken the single crystal structural determination of 2, in which the ciprofloxacin acts as tridentate bridging ligand; the complex exhibits a five-coordinated motif in a distorted square pyramidal environment around the metal center. The chemical nuclease activity of compounds 2 and 3 has also been studied, revealing that both compounds behave as efficient chemical nucleases in the presence of ascorbate. Mechanistic studies, with various radical oxygen scavengers, indicate that the DNA cleavage reaction is mediated by hydroxyl radicals, singlet oxygen, and the superoxide anion.
    Article · Jan 2009
  • [Show abstract] [Hide abstract] ABSTRACT: Fluoroquinolones are defined as an important group of synthetic antibacterial compounds, having a fluorine atom at position 6 and a piperazine ring at position 7 of quinolone-3-carboxylic acid. It was proved that the activity of quinolones was decreased in the environment of certain metal ions by the formation of sparingly soluble metal complexes. The proposed reason for such maintenance might be the chelate bonding of the quinolone to the metal. Again, it was proposed that metal ions, especially magnesium ions, were engaged in the mode of action of quinolones. In this review article, selected structures of fluoroquinolones metal complexes were performed and discussed in terms of their therapeutic application. The nuclease activity and antibacterial activity tests were presented and the effects of metal complexes were compared to free fluoroquinolones. Finally, the results were introduced.
    Full-text · Article · Feb 2009
  • [Show abstract] [Hide abstract] ABSTRACT: The aim of the present study was to evaluate factors contributing to the differences between the overall stability constants (log βpqr) of the fluoroquinolone–metal ion complexes.The experiments were performed using potentiometric titration method in wide pH range. The overall stability constants (log βpqr) were determined using the Hyperquad program. Complexation equilibria of eight different fluoroquinolones with six divalent and trivalent metal ions were investigated in this study.The authors employed a multifactorial ANOVA analysis, fixed effect model to describe the influence of particular variables affecting the stability of the analyzed complex species. Four different variables were set at different levels labeled. The ligand number (LF) was the first factor. LF determined the number of fluorochinolone molecules in the complex structure, and could take the values 1, 2 or 3. The second factor (Me) was connected with the type of the metal ion bonded in the complex. Since six different metal cations were studied, the Me factor was described with six levels. The number of hydrogen or hydroxide groups substituted into the complex molecule was the third variable (HR) with many levels labeled: q, a, s, d, f and g. The last factor FQ described the type of the fluorochinolone used for complex formations. All variables analyzed here were statistically significant (p value lower than 0.01), which indicates that all of them strongly affect the log βpqr value. Binary interactions (LF–Me, LF–FQ, Me–HR and Me–FQ) between variables were also stated, which suggests that the effects of these variables were higher than we could calculate based on the effect of each variable alone.The ANOVA analysis has shown that the following factors Me, LF and HR were the most important for the stability of the fluoroquinolone–metal ion complexes. It was also found that according to the FQ factor (type of ligand molecule) all analyzed fluoroquinolones formed stable complexes with metals. It was proved that the application of ANOVA for the entire complexation profile of analyzed fluoroquinolones with polyvalent metal ions was a valid technique for detecting the statistically significant differences in the complexation profiles. Such information may be very useful for better understanding and interpretation of differences in bioavailability of fluoroquinolones and their interactions with antacids and other multimineral drugs.
    Article · Aug 2009
  • [Show abstract] [Hide abstract] ABSTRACT: A mixed ligand coordination compound of copper with ofloxacin (oflo) and phenanthroline (phen) has been synthesized and characterized by means of X-ray single crystal diffraction and spectroscopic methods. Structural features of the coordination compound are described. CD and CV studies of the interactions of the title complex with calf thymus DNA (CT-DNA) show that the complex can bind to CT-DNA by intercalation and electrostatic binding modes. Antibacterial activities of the title compound, a Cu–oflo complex reported earlier and free oflo have been studied against different microorganisms. Both copper complexes enhance the antibacterial activities of the quinolone drugs. The inhibitory effect of the three compounds on two cancer cell lines was measured and the results indicate that the title complex has strongest inhibitory effect.
    Article · Oct 2009
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