Levofloxacin Molecules Research Articles

Molybdenum disulphide nanoparticles accelerate the transformation of levofloxacin in planting soil upon exposure

The use of nanocatalytic particles for the removal of refractory organics from wastewater is a rapidly growing area of environmental purification. However, little has been done to investigate the effects of nanoparticles on soil-plant systems with antibiotic contamination. This work assessed the effect of molybdenum disulfide (MoS2) on the soil-Phragmites communis system containing levofloxacin (LVX). The results showed that the addition of MoS2 had restoration potential for stressed plant. The MoS2 with catalytic activity promoted the transformation of LVX in rhizosphere soils. The transformation pathways of LVX in the different exposure groups were proposed. The continuous output of radicals in the high MoS2 dosage group facilitated the transformation of LVX to small molecule compounds, which were eventually mineralized. Moreover, the electron-density-difference analysis revealed the easier flow of electrons from the MoS2 surface towards the LVX molecules. This finding provides theoretical support for the application of nanocatalytic particles in ecological environments.

Valorization of heavy metals enriched ALB adsorbents as effective ZnS-CdS/C photocatalysts for antibiotics removal

Reutilizing heavy metal enriched adsorbents into efficient photocatalysts for antibiotic removal is of great economic value. Herein, spent alkali-lignin biochar (ALB) with enriched Zn2+/Cd2+ ions is valorized into ZnS-CdS/C photocatalyst via a simple vulcanization method. ZnS-CdS/C (3:1) exhibits a superior photocatalytic removal efficiency of 98.6 % for levofloxacin (LEV), with about 60 % of the initial value remained after four cycles. It also shows good photocatalytic removal efficiencies of 92.1 %, 95.4 % and 84.0 % for enrofloxacin, ciprofloxacin and tetracycline, respectively. Electron paramagnetic resonance (ESR) shows that the introduction of ZnS and CdS in ALB promotes the generation of oxygen vacancies and persistent free radicals (PFRs). The photocatalytic LEV removal mechanism of ZnS-CdS/C indicates that both the abundant PFRs and photogenerated electrons serve as electron donors, efficiently reducing dioxygen to superoxide free radicals (·O2-). The ·O2- formed in the above two ways continuously degrade the LEV molecules. Finally, the biotoxicity and developmental toxicity of LEV degradation intermediates confirms that the ZnS-CdS/C degradation system can remove LEV effectively with reduced harm to the ecological environment.

Drug repurposing study of levofloxacin: Structural properties, lipophilicity along with experimental and computational DNA binding

The process of developing new drug molecules is often lengthy, costly and labor-intensive, requiring several years to progress through clinical trials. However, in recent years, drug repurposing has emerged as a popular approach due to its ability to expedite the drug discovery process. By repurposing existing drugs for new therapeutic uses, valuable time and resources can be saved. Antibiotics, particularly fluoroquinolones have been reported to exhibit antitumor effects by reducing tumor growth and inducing cell cycle arrest. These antibiotics may disrupt specific cellular mechanisms, offering a potential avenue for novel anticancer treatments. Levofloxacin, a fluoroquinolone antibiotic, has a broad spectrum of action against certain bacteria, but its efficacy against most anaerobic bacteria is generally limited. In this study, the structural assessment and joint experimental – theoretical investigation was performed on its DNA binding ability mainly in molecular level from thermodynamics and mechanistic points of view. These include determining stability, charge delocalization, softness, reactivity and electrophilicity indices. Promising results were found in the assessment of this compound lipophilicity and stability. In addition, its interaction with DNA was investigated using both experimental analyses and molecular modeling techniques including molecular docking, molecular dynamics simulation and DFT via ONIOM procedure, demonstrating its binding to the minor groove of DNA through van der Waals/hydrogen bond forces. Based of experimental results, levofloxacin quenches the fluorescence of DNA through a static mechanism with the negative values for ΔH° and ΔS° thermodynamics quantities. Furthermore, one binding site on each DNA with 1000 nucleotides is available for each levofloxacin molecule.

Research on the sustainable effect of ZnS and MoS2 decorated biochar nanocomposites for removing quinolones from antibiotic-polluted aqueous solutions

Antibiotic concentrations in wastewater generated by industries such as sewage treatment plants, medical pharmaceuticals and aquaculture has exceeded acceptable levels. It is particularly urgent to seek a method that can efficiently remove antibiotics. The removal potential of three quinolone antibiotics, pefloxacin (PF), levofloxacin (LF) and norfloxacin (NF), in simulated contaminated water was studied using a biochar-based nanomaterial prepared by a hydrothermal method. The data were fitted with adsorption kinetics, isotherms and thermodynamics. The results showed that ZnS–MoS2 activated biochar (ZMMBC) acheived maximum adsorption amounts of 199.42, 125.00 and 142.58 mg g–1 for PF, LF and NF, suggesting that ZMMBC has excellent adsorption performance. The adsorption mechanisms of PF, LF and NF molecules on ZMMBC include complexation, pore filling, π–π interactions, electrostatic interactions and hydrogen bond interactions.

Comparing the electrochemical degradation of levofloxacin using the modified Ti/SnO2 electrode in different electrolytes

The purpose of this study is to develop an electrode material with high electrocatalytic activity, good stability and low price for the degradation of the new pollutant - antibiotic levofloxacin (LEV). A novel modified Ti/SnO2 electrode is prepared using a sol–gel method combined with spraying. The morphology of the Ti/SnO2-Sb-Ni/SiO2 electrode was performed by field emission scanning electron microscopy, which revealed a smooth and flat surface. It can be seen from the results of X-ray diffraction and electrochemical tests, the electrode possessed finer grain size (2.68 nm) and slightly higher oxygen evolution potential (OEP, 1.87 V). Electrochemical degradation experiments show that the removal rate of LEV in Na2SO4 and NaNO3 solutions reached 100% after 10 min reaction, while in NaCl solution the reaction time (LEV 100% removal) was shortened to 3 min, indicating a faster removal rate. An electrical energy consumption per order of magnitude (EE/O) of LEV degraded by Ti/SnO2-Sb-Ni/SiO2 electrode was only 0.59 kWh m−3 for an initial concentration of 20 mg/L LEV with a volume of 400 mL. According to the changes of UV–visible absorption spectra during the LEV degradation, the damage degree of conjugated structures in LEV molecules varies with different electrolytes. The existence of hydroxyl radical (•OH) and sulfate radical (SO4•−) was confirmed by radical quenching experiment and EPR text with 100 mM 5,5-Dimethyl-1-pyrrolidine N-oxide (DMPO). In different electrolytes, SO4•− (in Na2SO4 solution), •OH (in NaNO3 solution) and active chlorine(in NaCl solution) played a leading role in LEV degradation, respectively.

Insight into the inhibitory roles of ionic liquids in the adsorption of levofloxacin onto clay minerals

The ionic liquids may have an impact on the interactions between fluoroquinolone antibiotics and clay minerals, which are widespread in nature. This work evaluated the adsorption properties of levofloxacin onto three clay minerals (i.e., montmorillonite, vermiculite, and kaolinite) affected by three types of soluble imidazolium-based ionic liquids with different chain lengths of cations ([C2mim]Cl, [C4mim]Cl, and [C6mim]Cl). The results demonstrated that the levofloxacin-binding capacity varied according to clay type (i.e., montmorillonite > vermiculite > kaolinite) regardless of ionic liquids-free or ionic liquids-addition. The observation was made concerning the physical-chemical characteristics of different clay minerals (e.g., physical structure, surface functional groups, specific surface area, and cation exchange capacity). Interestingly, ionic liquids suppressed levofloxacin adsorption on the three test clay minerals because of steric hindrance effects induced by the adsorbed ionic liquids as well as the site competition during co-adsorption of levofloxacin molecules and cations of ionic liquids. Additionally, the inhibitory impacts of ionic liquids in the sequence of [C6mim]Cl > [C4mim]Cl > [C2mim]Cl stemmed from steric hindrance and site competition during co-adsorption of ionic liquids and levofloxacin increased with chain lengths of ionic liquids. Another interesting finding was that the extent of inhibitory effects of [C4mim]Cl increased with the rise of pH values from 5.0 to 9.0, owing to the greater adsorption competition and steric effects derived from more adsorbed [C4mim]+ at higher pH conditions. The findings of this study are critical in assessing the effects of emerging contaminants on the fate of antibiotics in eco-environmental systems.

Coordination activation enhanced photocatalytic performance for levofloxacin degradation over defect-rich WO3 nanosheets

The defect-rich ultrathin WO3 nanosheets are successfully prepared as photocatalysts via heating treatment for the pristine WO3 nanosheets (NS) in vacuum (NSV) and N2 atmosphere (NSN). The increment of degradation efficiencies of levofloxacin (LVX) over NS (49.9 %) <NSN (75.9 %) <NSV (84.3 %) under visible light is mainly due to the increase of oxygen vacancies (OVS). These OVS have the potential to generate more unsaturated W centers (Lewis acid sites) which are beneficial to activate the CO of carboxyl and the C-N of piperazinyl in LVX molecules via W…OC and W…N-C coordination. LC-MS result further demonstrates that the LVX molecules breakdown are mainly initiated by cleaving the activated CO and C-N bonds. More OVS can adsorb and activate more O2 molecules which shall be converted to •O2− by photogenerated electron. The photogenerated holes are transferred on the catalysts surface to form •OH via oxidizing water or directly degrade the activated LVX molecules. Finally, a possible mechanism is proposed to understand the pathway for photocatalytic degradation LVX at molecular scale. This study highlights the significant role of coordination activation for the photocatalytic degradation of antibiotics.

Enhanced decontamination of Levofloxacin residuals from water using recycled glass based a green zinc oxide/mesoporous silica nanocomposite; adsorption and advanced oxidation studies

Glass solid wastes were recycled in the synthesis of green zinc oxide/mesoporous silica (MCM-41) composite with significant surface area (661 m2/g) and bandgap energy (2.43 eV). It was assessed as a potential adsorbent and photocatalyst for Levofloxacin. The Levofloxacin adsorption reaction is of First-order kinetic (R2 = 0.99) and Langmuir isotherm properties (R2 > 0.95). A monolayer model with two energy sites was applied for more details about the adsorption process (R2 = 0.999). Considering the steric parameters, the adsorbed Levofloxacin molecules (n) are higher than 1 on both sites (n1 (2.6–5.15) and n2 (2.99–3.18)). This suggested vertical adsorption of several Levofloxacin molecules per site by a multimolecular mechanism. The active site densities of zinc oxide as the first site (Nm1) and saturation capacity (Qsat1) increased with temperature up to 45 °C (Nm1 = 17.8 mg/g and Qsat1 = 57.49 mg/g). The reverse occurred for the second sites (MCM-41) and the best values were reported at 25 °C (Nm2 = 23.35 mg/g and Qsat2 = 69.8 mg/g). The adsorption energy (−8.16 to −25.9 kJ/mol) and thermodynamic functions declare physical Levofloxacin uptake mechanisms of spontaneous and exothermic properties. G.Zn/MCM as photocatalyst (0.5 g/L) achieved 100% oxidation of Levofloxacin (50 mg/L) and 100% mineralization after 160 min and 240 min, respectively.

Parallel-slipped π−π electron-donor−acceptor in adsorption process: Molecular dynamics simulation

Molecular dynamics simulation was used to study the adsorption of single wall carbon nanotubes (SCNT) in levofloxacin (LEV) solutions of different concentrations by Radial distribution function, mean square displacement and interaction energy. The results showed that levofloxacin molecules were adsorbed around the carbon nanotubes. The adsorption effect of large concentration solution was not as good as that of low concentration solution because of agglomeration. LEV molecules with different concentration were free diffusion within 15ns, and gradually agglomerated under the influence of adsorption. The energy change is proportional to the concentration of the molecule. The distance between benzene rings corresponding to the agglomeration effect of levofloxacin molecules was 0.4 nm, which should be the effect of parallel-slipped π−π electron-donor−acceptor (EDA) interactions. The simulation results are valuable to study the adsorption and removal of benzenes by adsorbent.

Competitive adsorption of ofloxacin enantiomers to goethite: experiments and modelling

Environmental contextThe concentration, types and distribution of antibiotics in soils can have environmental effects and can be modelled using laboratory systems. Adsorption of ofloxacin (OFL) and levofloxacin (LEV) enantiomers to goethite can probe this behaviour and each binds differently to the solid phase. The different behaviour of LEV and OFL in relation to solid-solution partitioning will affect their environmental fate. AbstractThe adsorption of ofloxacin enantiomers, namely levofloxacin (LEV) and ofloxacin (OFL), to goethite was investigated using batch experiments. Structural information of aqueous and adsorbed LEV or OFL was obtained with ultraviolet–visible (UV-Vis), three-dimensional excitation–emission matrix (EEM) and attenuated total reflectance Fourier-transform infrared (ATR-FTIR) spectroscopic methods. The results indicated that LEV molecules formed a bridging bidentate complex (≡(FeO)2–LEV) with the surface of goethite, and OFL formed a monodentate complex (≡FeO–OFL). The adsorption of OFL to goethite was stronger than that of LEV, owing to differences in their physicochemical properties and bonding modes. The adsorption of LEV and OFL to goethite in single systems was well simulated using the charge distribution multi-site complexation (CD-MUSIC) model, but their adsorption in the LEV–OFL–goethite systems was overestimated at pH ~5.2 and high concentrations of LEV–OFL mixture (19.59μM), in which the predicted amounts of adsorbed LEV and OFL were higher (20.0, 30.8%) than the experimental results. Compared with the unprotonated LEV or OFL, the protonated (&amp;gt;99.9%) ones were mainly adsorbed to the surface of goethite, and the single species may be used during their following modelling.

Reply to the ‘Comment on “Polymorphism of levofloxacin: structure, properties and phase transformation”’ by Tejender S. Thakur, CrystEngComm, 2020, 22, DOI: 10.1039/C9CE01400D

Minor structural differences in molecular conformation were found where the levofloxacin molecule takes a less stable conformer in energy rather than the stable conformer as previously expected.

An effective strategy for boosting photoinduced charge separation of Ag3PO4 by BiVO4 with enhanced visible light photodegradation efficiency for levofloxacin and methylene blue.

In this paper, a Z-scheme Ag3PO4/BiVO4 photocatalyst was successfully prepared by precipitation-deposition method. The Ag3PO4/BiVO4 composite exhibited enhanced photocatalytic activity and recyclability for levofloxacin and methylene blue degradation under visible light irradiation. In the Ag3PO4/BiVO4-0.4 system, up to 92.44% of the levofloxacin molecules can be decomposed within 180min and the photocatalytic degradation efficiency can maintain at 92.02% for methylene blue after recycled for 5 times. The enhanced photocatalytic activity of Ag3PO4/BiVO4 heterojunctions could be mainly attributed to the fabrication of hetero-structure between BiVO4 and Ag3PO4. The photogenerated electron-hole pair separation was effectively enhanced based on the photocurrent, electro-chemical impedance spectra and photoluminescence data. Furthermore, the electrons transfer from photoinduced BiVO4 to Ag3PO4 and the visible light harvesting efficiencies were significantly increased due to the BiVO4 hybridization. The ·OH was the main oxidative species in the Ag3PO4/BiVO4 system for the methylene blue decomposition. Finally, a purposed photocatalytic mechanism for methylene blue degradation was discussed in detail on the basis of experimental results.

Separation of Levofloxacin from Industry Effluents Using Novel Magnetic Nanocomposite and Membranes Hybrid Processes.

Magnetic carbon nanocomposite (MCN) was synthesized from waste biomass precursor, pineapple. The prepared adsorbent was characterized using different instrumental techniques and was used to remove levofloxacin (LEV) from effluents. The maximum sorption of LEV was observed at pH 7. Pseudo-2nd-order (PSO) kinetic was found to be the best model that fits well the adsorption kinetics data. For Langmuir adsorption isotherm, the R2 value was higher as compared with other isotherms. The Van't Hoff equation was used for thermodynamic parameters determinations. ΔS° (standard entropy) was positive and ΔG° (standard Gibb's free energy) was negative: -0.37, -1.81, and -3.73 kJmol−1 corresponding to 25, 40, and 60°C. The negative values of ΔG° at different temperatures stipulate that the adsorption of LEV was spontaneous in nature and adsorbent has a considerable affinity for LEV molecules. The MCN was then utilized in hybrid way by connecting with ultrafiltration (UF), nanofiltration (NF), and reverse osmosis (RO) membranes in series and as a result enhanced permeate fluxes were observed. The percent retention of LEV molecules was lower with UF membrane and with NF it was 96%, while it was 100% with RO. For MCN/UF and MCN/NF systems, improvement in % retention was recorded.

Adsorption of levofloxacin onto mechanochemistry treated zeolite: Modeling and site energy distribution analysis

Adsorption of antibiotic levofloxacin from aqueous solution to humic acid treated zeolite has been studied. The equilibrium isotherm model was calculated and the site energy distribution was determined. Within the test range (initial concentration 5.5–67 mg/L, pH 2–12), adsorption performance for levofloxacin showed two maximum total uptakes at acid and alkali conditions. The uptake capacities are 33.93 mg/g and 35.98 mg/g at pH 4.85 and pH 9.44, respectively. Due to the equilibrium isotherm model, the theoretical maximum value of adsorbent capacities of levofloxacin are 35.45 mg/g and 47.68 mg/g at pH 4.85 and pH 9.44. The site energy distribution of the adsorbent for levofloxacin molecules adsorption was estimated. The higher average site energy of the adsorbents is 28.01 kJ/ mol at pH 4.85. The methods of site energy distribution analysis could be transferable to extend other organics and inorganics adsorption.

Construction of optimized Au@Ag core-shell nanorods for ultralow SERS detection of antibiotic levofloxacin molecules.

The abuse of antibiotics in animal husbandry has been regarded as a daunting public health risk, facilitating the emergence and spread of resistant pathogens to humans. Herein, bimetallic Au@Ag core-shell nanorods (NRs) with precise, controllable Ag shell-thickness (2.1~14.1 nm) were fabricated and developed for ultralow detection of levofloxacin molecules using surface enhanced Raman scattering spectroscopy (SERS). We found that the Au@Ag NRs with 7.3 nm Ag shell-thickness provided maximized SERS activity in comparison with other as-prepared nanosubstrates in this paper. The detection limit of levofloxacin molecules was achieved at a nanomole (nM) level of 0.37 ng/L (10-9 M), providing ultrasensitive assessment of antibiotics in natural ecosystems.

Crystal Structure and Properties of Levofloxacinium 2-Thiobarbiturate Trihydrate

The structure of levofloxacinium 2-thiobarbiturate trihydrate LevoH 2 + Htba–·3H2O (I) (LevoH is levofloxacin, H2tba is 2-thiobarbituric acid) is determined (CIF file CCDC No. 1547466); its thermal decomposition and IR spectrum are studied. The crystals of I are triclinic: a = 8.670(1) A, b = 9.605(1) A, c = 15.786(2) A, α = 89.144(5)°, β = 88.279(5)°, γ = 76.068(5)°, V = 1275.4(3) A3, space group P1, Z = 2. The unit cell of I contains two LevoH 2 + ions, two Htba– ions, and six H2O molecules. The absolute structure of the crystal and the configuration of the chiral center in a levofloxacin molecule S are determined. Experiments for generating the second optical harmonics gave a positive result. Intermolecular hydrogen bonds (HBs) N–H···O and O–H···O in I form a bilayer system along the ab diagonal with hydrophilic moieties within a layer and hydrophobic moieties directed outward. The structure is stabilized by multiple HBs and the π–π interaction between the Htba–and LevoH 2 + ions and between the LevoH 2 + ions.

Voltammetric, spectroscopic and thermal investigations of the interaction of levofloxacin with cysteine at physiological pH

In this study, levofloxacin (LEVOF) hemihydrate interaction with L-cysteine (RSH) was investigated by using square-wave voltammetry (SWV) in Britton–Robinson (B–R) buffer pH 7.4. Addition of the LEVOF to RSH solution resulted in dropping of the main reduction peak current of RSH (the current of mercurous cysteine thiolate Hg2(RS)2). The vary in the peak current of Hg2(RS)2, after the adding of the LEVOF is indicated an interaction between RSH and LEVOF molecules. Moreover, the interaction between two molecules also confirmed with UV-Vis, FT-IR spectroscopic measurements and thermal analysis data. Binding constant of LEVOF with RSH was calculated by both voltammetric and UV-Vis spectroscopic data.

Porous nano-cerium oxide wood chip biochar composites for aqueous levofloxacin removal and sorption mechanism insights.

The adsorption removal of levofloxacin (LEV), a widely used fluoroquinolone antibiotic, by using the biochars derived from the pyrolysis of pine wood chip pretreated with cerium trichloride was investigated through batch sorption experiments and multiple characterization techniques. The differences in the basic physicochemical properties between Ce-impregnated biochars and the pristine biochars were confirmed by the analysis of elemental compositions, specific surface areas, energy dispersive spectrometry, X-ray diffraction, and thermo-gravimetry. FT-IR spectra of the pre- and post-sorption biochars confirmed the chemical adsorption for LEV sorption onto the biochars. Large shifts in the binding energy of Ce3d, O1s, C1s, and N1s regions on the pre- and post-sorption biochars indicated the surface complexation of LEV molecule onto the biochars. The binding species of Ce4+ and Ce3+ identified by X-ray photoelectron spectroscopy reflect the role of Ce oxides during sorption. Batch adsorption showed the significant enhancement of adsorption capacity for LEV after the Ce modification. Batch adsorption kinetic data fitted well with the pseudo-second-order model. Both the Langmuir and the Freundlich models reproduced the isotherm data well. Findings from this work indicated that Ce-impregnated biochars can be effective for the removal of aqueous LEV.

SERS investigation and detection of levofloxacin drug molecules on semiconductor TiO2: Charge transfer contribution

In this work, TiO2 and Zn doped TiO2 nanoparticles (Zn-TiO2 NPs) were synthesized and served as SERS-active substrate for the detection of levofloxacin (LVFX) drug molecules. Both experimental and theoretical methods are used to study the enhanced mechanism and interaction between substrate and drug molecule. The results indicate that the LVFX is close to the substrate surface through the carboxyl group. The levofloxacin molecules adsorbed on Zn-TiO2 NPs exhibit the largest SERS enhancement, when the Zn content is 3%, the adsorption time is 7h and pH value is 6.78. The detection limit can be reduced to 1.29×10−7mol/L by this method. And, a quantitative detection method of LVFX can be established. There is a good linear relationship in the range of 1×10−3–1×10−7mol/L concentration.

Modeling and site energy distribution analysis of levofloxacin sorption by biosorbents

An adsorption equilibrium model was applied to simulate the sorption of an antibiotic, levofloxacin (LEV), one of the emerging contaminants, from aqueous solution by the biosorbent based on pretreated barley straw. The effects of solution pH, contact time, LEV concentration and ionic strength on LEV removal were investigated, and desorption of LEV loaded on pretreated barley straw was also examined. In addition, site energy distribution of the pretreated biosorbent for LEV molecules adsorption was estimated. The average site energy and standard deviation of the site energy distribution under various pH values were determined and applied to analyze the interaction between the biosorbent and adsorbate, and sorption site heterogeneity. With higher average site energy (28.1kJ/mol), the pretreated barley straw at neutral pH had higher sorption affinity, thus be more favorable for the sorption reaction than the lower affinity surface at acidic or basic pH. The experimentally achieved LEV uptake of the pretreated barley straw at pH 6.88 is much higher than that of raw barley straw, and other sorbents reported in literatures. The methods of biomass pretreatment and site energy distribution analysis could be transferable to extended organics or inorganics adsorption by biosorbents.