Structure of levofloxacin in hydrophilic and hydrophobic media: Relationship to its antibacterial properties

Lambert, Alexandrine; Regnouf‐de‐Vains, Jean‐Bernard; Ruiz‐López, Manuel F.

doi:10.1016/j.cplett.2007.05.077

Cited by 22 publications

(14 citation statements)

References 25 publications

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“…The fluoroquinolones such as LVF (selected as one of the representative fluoroquinolone antibiotic) have pH 5.53 for LVF‐free μE and 7.25 LVF‐loaded μE, respectively. Fluoroquinolones in water exhibits a zwitterionic structure at a pH close to seven . Increase in pH value after LVF loading may be due to the zwitterionic behaviour of LVF.…”

Section: Resultsmentioning

confidence: 99%

Structural Insights into the Microemulsion‐Mediated Formation of Fluoroquinolone Nanoantibiotics

et al. 2018

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Microemulsions (μEs) are being exploited as a potential route for yielding an extensive range of nanoparticles of different chemical nature, shapes and sizes. Nanodrugs offer new avenues for structuring better “drug delivery systems”. In this study, an oil‐in‐water (o/w) μE formulation comprising N‐butyl acetate/polysorbate 80/ethanol/water was developed for the preparation of nanoparticles of fluoroquinolone antibiotics (FLQ‐NPs). A pseudoternary phase diagram was mapped at constant surfactant/cosurfactant (1:2), revealing improved and high loading of FLQs in an optimum μE formulation. The as‐formulated μE showed high loading of FLQs as; levofloxacin (4.20 wt.%), ciprofloxacin (3.16 wt.%), moxifloxacin (2.53 wt.%), gatifloxacin (1.36 wt.%), ofloxacin (0.70 wt.%). Fourier transform IR analysis indicated good compatibility of each FLQ drug with μE excipients. However, dynamic light scattering showed an increase in the average particle size of the μE on drug loading, indicating the accumulation of FLQ at interface layer of the micelle. Additionally, lyophilized levofloxacin (a selected antibiotic) showed long‐term stability, amorphous morphology and improved dissolution rate, inspected by scanning transmission electron microscopy, X‐ray diffraction and electronic spectroscopy, respectively. Moreover, fluorescence measurements suggested the interfacial vicinity of levofloxacin within the μE domain, which may support controlled release of drug during systemic circulation.

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Section: Resultsmentioning

confidence: 99%

Structural Insights into the Microemulsion‐Mediated Formation of Fluoroquinolone Nanoantibiotics

et al. 2018

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“…Indeed, it is now well established that explicit consideration of water molecules in the first solvation shell is important to stabilize zwitterions [51][52][53] and many studies of amino acids in water have successfully employed a hybrid discrete-continuum approach. [5, 16, 17, 20, 54-59, 60, 61] When the number of first-shell water molecules is large (as for the dimeric systems studied herein), statistical analysis of conformations becomes a fundamental question.…”

mentioning

confidence: 99%

Glycine Dimers: Structure, Stability, and Medium Effects

Friant-Michel

Ruiz‐López

2010

ChemPhysChem

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We report a study on different ionization states and conformations of the bimolecular (Gly)(2) system by means of quantum mechanical calculations. Optimized geometries for energy minima of the glycine dimer, as well as relative energies and free energies were computed as a function of the medium: gas phase, nonpolar polarizable solvent, and aqueous solution. The polarizable continuum model was employed to account for solvation effects. Energy calculations were done using the MP2/aug-cc-pVTZ and B3LYP/6-311+G(2df,2p) methods on B3LYP/6-31+G(d,p) optimized structures (some single-point energy calculations were also done using the B3PW91 and PBE1KCIS methods). Ionized forms of the glycine dimer (either zwitterion-zwitterion or neutral-zwitterion) are predicted to exist in all media, in contrast to amino acid monomers. In aqueous solution, dimerization is an exergonic process (-4 kcal mol(-1)). Thus, according to our results, zwitterion-zwitterion Gly dimers might be abundant in supersaturated glycine aqueous solutions, a fact that has been connected with the structure of α-glycine crystals but that remains controversial in the literature. Another noticeable result is that zwitterion-zwitterion interactions are substantially underestimated when computed using methods based on density functional theory. For comparison, some calculations for the dimer of the simplest chiral amino acid alanine were done as well and differences to the glycine dimer are discussed.

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“…34 Furthermore, no out-of plane vibrations are detected in the 900-600 cm À1 region. This was assigned to the in-plane mode of the of the quinolone ring system.…”

Section: Spectroscopic Characterization Of Levomentioning

confidence: 94%

“…34 Generally, regardless of the preparation protocol, different salts are added to the Ag colloids in order to overcome the electrostatic repulsion between the particles. The Raman modes with the highest intensities present in the case of the saturated aqueous solution are centred at 1614 cm À1 and 1395 cm À1 .…”

Section: Spectroscopic Characterization Of Levomentioning

confidence: 99%

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Droplet based microfluidics: spectroscopic characterization of levofloxacin and its SERS detection

Hidi

Jahn

Weber

et al. 2015

Phys. Chem. Chem. Phys.

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Levofloxacin (Levo), a second generation fluoroquinolone, has both clinical and environmental relevance. Therefore, the implementation of fast, robust and cost effective techniques for its monitoring is required. Here, its spectroscopic characterization and its detection in aqueous environment were carried out using surface enhanced Raman spectroscopy combined with droplet based microfluidics. The Levo molecule interacts with the silver nanoparticles via the carboxylate group and it adopts an upright or slightly tilted orientation. Furthermore, it is shown that the presence of Cl(-) ions has a strong influence on the enhancement efficiency of the Raman signal of the target molecule. Thus, for the determination of the limit of detection (LOD) the measurements were carried out in the absence of any electrolytes. The estimated LOD is ∼0.8 μM and the linear dynamic window ranges between 1-15 μM. These results were achieved after the normalization of the SERS signal to the Raman mode at 230 cm(-1). This band was attributed to the ν(Ag-O) stretching and it accounts for the Levo molecules in the first layer on the Ag nanoparticles.

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Structure of levofloxacin in hydrophilic and hydrophobic media: Relationship to its antibacterial properties

Cited by 22 publications

References 25 publications

Structural Insights into the Microemulsion‐Mediated Formation of Fluoroquinolone Nanoantibiotics

Structural Insights into the Microemulsion‐Mediated Formation of Fluoroquinolone Nanoantibiotics

Glycine Dimers: Structure, Stability, and Medium Effects

Droplet based microfluidics: spectroscopic characterization of levofloxacin and its SERS detection

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