Exploring the economic viability of electrochemical assessment for water contaminants with NiFe-PBA/ZIF-67 core shell modified GCE.

Zeolitic Imidazolate (metal organic) Frameworks (ZIFs) and Prussian Blue Analogues (PBAs) are promising materials in electrochemical sensing due to their unique properties. In this study, a composite material comprising NiFe-PBA and ZIF-67 was synthesized and made to form a uniform layer onto a glassy carbon electrode (GCE) to enhance electrochemical performance for furazolidone (FZD) detection. The synthesized NiFe-PBA/ZIF-67 composite exhibited excellent sensitivity, selectivity, and stability towards FZD detection, with a low limit of detection (LOD). The electrochemical behaviour of FZD on the NiFe-PBA/ZIF-67/GCE electrode was investigated, revealing a diffusion-controlled process. Differential pulse voltammetry (DPV) analysis demonstrated the synergetic effect of the PBA/MOF core-shell structure in enhancing FZD electro-reduction. The sensor exhibited exceptional LOD of 0.007 µM. Selectivity studies confirmed the sensor's ability to distinguish FZD from potential interferents. Extensive evaluations demonstrated the sensor's reproducibility, repeatability, and long-term stability, affirming its practical utility. Real sample analysis further validated the sensor's excellent analytical capabilities in diverse matrices.

Colorimetric immunoassay of furazolidone metabolites based on iron-copper bimetallic organic framework nanoenzyme.

Based on the peroxidase activity of Cu-hemin metal-organic framework (Cu-hemin MOF) nanozyme, a colorimetric enzyme-linked immunosensor was developed for the detection of furazolidone (FZD). Cu-hemin MOF is a bimetallic nanozyme that exhibited a stronger catalytic effect compared with single-metal organic framework nanoenzymes. Cu-hemin-MOF catalyzes hydrogen peroxide (H2O2) to produce hydroxyl radicals (•OH), which oxidizes the chromogenic substrate 3,3',5,5'-tetramethylbenzidine (TMB) to blue oxidized TMB (oxTMB). The absorbance change is at 650 nm. The content of AOZ in animal food can be quickly and accurately determined by changes in absorbance. The linear range of the colorimetric biosensor for detecting FZD was 0.01 ~ 62.52 ng/mL, and the limit of detection was as low as 0.01 ng/mL. The recovery of spikes samples was in the range 94.2-108.0 % and reproducibility was less than 4.8%. In addition, the cross-reaction rate was less than 0.1% when detecting other metabolites except AOZ, indicating that the sensor has good applicability and specificity. This study not only provides a better understanding of the relationship between the dispersion of nanoenzymes and enzyme-like activity but also offers a general method for detecting antibiotics using the nanoenzyme colorimetric method.

A Combined Experimental and Theoretical Study of Nitrofuran Antibiotics: Crystal Structures, DFT Computations, Sublimation and Solution Thermodynamics.

Single crystal of furazolidone (FZL) has been successfully obtained, and its crystal structure has been determined. Common and distinctive features of furazolidone and nitrofurantoin (NFT) crystal packing have been discussed. Combined use of QTAIMC and Hirshfeld surface analysis allowed characterizing the non-covalent interactions in both crystals. Thermophysical characteristics and decomposition of NFT and FZL have been studied by differential scanning calorimetry (DSC), thermogravimetric analysis (TG) and mass-spectrometry. The saturated vapor pressures of the compounds have been measured using the transpiration method, and the standard thermodynamic functions of sublimation were calculated. It was revealed that the sublimation enthalpy and Gibbs energy of NFT are both higher than those for FZL, but a gain in the crystal lattice energy of NFT is leveled by an entropy increase. The solubility processes of the studied compounds in buffer solutions with pH 2.0, 7.4 and in 1-octanol was investigated at four temperatures from 298.15 to 313.15 K by the saturation shake-flask method. The thermodynamic functions of the dissolution and solvation processes of the studied compounds have been calculated based on the experimental data. Due to the fact that NFT is unstable in buffer solutions and undergoes a solution-mediated transformation from an anhydrate form to monohydrate in the solid state, the thermophysical characteristics and dissolution thermodynamics of the monohydrate were also investigated. It was demonstrated that a combination of experimental and theoretical methods allows performing an in-depth study of the relationships between the molecular and crystal structure and pharmaceutically relevant properties of nitrofuran antibiotics.

Depicting the binding of furazolidone/furacilin with DNA by multiple spectroscopies, voltammetric as well as molecular docking.

The interaction between DNA and furazolidone/furacillin was investigated using various analytical techniques including spectroscopy and electroanalysis and molecular modelling. With the aid of acridine orange (AO), the fluorescence lifetimes of DNA-AO, DNA-furazolidone/furacillin-AO remained almost the same, which proved that the ground state complex was formed due to furazolidone/furacillin binding with DNA. Circular dichroism spectra and Fourier transform infrared spectroscopy showed that the second structure of DNA changed. Viscosity experiments presented that relative viscosity of DNA was increased with the increasing concentrations of furazolidone and almost unchanged for furacilin. In addition, the results of melting temperature (Tm ), ionic strength, site competition experiments, cyclic voltammetry, and molecular docking all proved the intercalation binding mode for furazolidone and groove binding mode for furacilin. The binding constants (Ka ) obtained from Wolfe-Shimmer equation were calculated as 3.66 × 104 L mol-1 and 3.95 × 104 L mol-1 for furazolidone-DNA and furacilin-DNA, respectively.

Novel 5-Nitrofuran-Activating Reductase in Escherichia coli.

The global spread of multidrug-resistant enterobacteria warrants new strategies to combat these pathogens. One possible approach is the reconsideration of "old" antimicrobials, which remain effective after decades of use. Synthetic 5-nitrofurans such as furazolidone, nitrofurantoin, and nitrofurazone are such a class of antimicrobial drugs. Recent epidemiological data showed a very low prevalence of resistance to this antimicrobial class among clinical Escherichia coli isolates in various parts of the world, forecasting the increasing importance of its uses to battle antibiotic-resistant enterobacteria. However, although they have had a long history of clinical use, a detailed understanding of the 5-nitrofurans' mechanisms of action remains limited. Nitrofurans are known as prodrugs that are activated in E. coli by reduction catalyzed by two redundant nitroreductases, NfsA and NfsB. Furazolidone, nevertheless, retains relatively significant antibacterial activity in the nitroreductase-deficient ΔnfsA ΔnfsBE. coli strain, indicating the presence of additional activating enzymes and/or antibacterial activity of the unreduced form. Using genome sequencing, genetic, biochemical, and bioinformatic approaches, we discovered a novel 5-nitrofuran-activating enzyme, AhpF, in E. coli The discovery of a new nitrofuran-reducing enzyme opens new avenues for overcoming 5-nitrofuran resistance, such as designing nitrofuran analogues with higher affinity for AhpF or screening for adjuvants that enhance AhpF expression.

Pharmacokinetics and tissue distribution of furanodiene W/O/W multiple emulsions in rats by a fast and sensitive HPLC-APCI-MS/MS method.

A sensitive and specific HPLC-APCI-MS/MS method was developed and validated for the quantification of furanodiene, a natural antitumor compound in rat plasma and tissues. W/O/W multiple emulsions of furanodiene, identified through microscope-observation and eosin staining method, were prepared with a two-step-procedure. Pharmacokinetics and tissue distribution were studied in rats after oral, intraperitoneal and intravenous injection with the dose of 5, 10 and 50 mg/kg, respectively. The assay achieved a good sensitivity and specificity for the determination of furanodiene in biological samples. The results showed that the concentration-time curves of furanodiene in rats after intravenous injection were fitted to a two-compartment model and the linear pharmacokinetic characteristic. The highest concentration in rat tissue was observed in the spleen, followed by heart, liver, lung, kidney, small intestine and brain. Comparing with the low concentration in plasma, furanodiene could be detected in various tissue samples after oral or intraperitoneal injection which indicated furanodiene had good and rapid tissue uptake. The results suggested that the wide tissue distribution of furanodiene could conduce to the therapeutic effects, but the short biological half-life limited its further application as an antitumor agent. The results are helpful for the structure modification of furanodiene as an antitumor candidate.

Lateral flow immunoassay for furazolidone point-of-care testing: Cater to the call of saving time, labor, and cost by coomassie brilliant blue labeling.

Furazolidone (FZD) and its metabolite called 3-amino-2-oxazolidinone (AOZ) would induce carcinogenic and mutagenic effects to human. In this work, to develop a novel, stable, and simple point of care testing (POCT) with a potential to social applied for FZD detection, we utilized the aspect of protein staining of coomassie brilliant blue (CBB) to exploit a new CBB-LFIA strategy free of NPs. Only one mixing step is needed during the probe manufacturing process, which requires just 2 h and is a great time saving strategy compared with other methods (requiring 4-33 h for probe preparation). Besides, the cost of CBB-LFIA is 300 times lesser than other LFIA with respect to obtaining the label. The developed CBB-LFIA was successfully applied to detect AOZ with a detection limit of 2 ng mL-1, without any influence from other potential interfering compounds. The proposed CBB-LFIA exhibited prominent practical application, and possesses considerable utilization potential in the related field.

Furazolidone Increases Survival of Mice Exposed to Lethal Total Body Irradiation through the Antiapoptosis and Antiautophagy Mechanism.

Exposure to total body irradiation (TBI) causes dose- and tissue-specific lethality. However, there are few effective and nontoxic radiation countermeasures for the radiation injury. In the current study, mice were pretreated with a traditional antimicrobial agent, FZD, before TBI; the protective effects of FZD on radiation injury were evaluated by using parameters such as the spleen index and thymus index, immunohistochemical staining of intestinal tissue, and frequency of micronuclei in polychromatophilic erythrocytes of bone marrow. The intestinal epithelial cell line IEC-6 was used to investigate the underlying mechanisms. Our results indicated that FZD administration significantly improved the survival of lethal dose-irradiated mice, decreased the number of micronuclei, upregulated the number of leukocytes and immune organ indices, and restored intestinal integrity in mice after TBI. TUNEL and western blot showed that FZD protected intestinal tissue by downregulating radiation-induced apoptosis and autophagy. Meanwhile, FZD protected IEC-6 cells from radiation-induced cell death by inhibiting apoptosis and autophagy. To sum up, FZD protected against radiation-induced cell death both in vitro and in vivo through antiapoptosis and antiautophagy mechanisms.

The anti-infection drug furazolidone inhibits NF-κB signaling and induces cell apoptosis in small cell lung cancer.

Targeting nuclear factor kappa B (NF-κB) signaling pathway has become a promising strategy for the development of new antitumor drugs. In this paper, we found that anti-infection drug furazolidone (FZD) could significantly inhibit NF-κB-driven luciferase activity, and FZD could markedly inhibit both of the constitutive and tumor necrosis factor-α (TNFα)-triggered phosphorylation of NF-κB p65 in small cell lung cancer (SCLC). Further studies revealed that FZD inhibited the expression of inhibitor of kappa B kinase ß (IKKß) in SCLC cells. In addition, we found that FZD had significant antitumor activities in SCLC cells. FZD could markedly suppress the cell viability of SCLC cells dose-dependently, and FZD could significantly induce the cleavages of poly ADP-ribose polymerase (PARP) and Caspase3, the biomarkers of cell apoptosis, in SCLC cells. The flow cytometry also revealed that FZD induced cell apoptosis in SCLC cells. Finally, we also found that overexpression of constitutively activated IKKß could significantly abolish FZD-induced cell growth inhibition in SCLC cells, which further confirmed that FZD displayed its anti-SCLC activity through regulating NF-κB signaling pathway.

Ultrasonic preparation of near-infrared emission cluster-based YbIII and NdIII coordination materials: Ratiometric temperature sensing, selective antibiotics detection and "turn-on" discrimination of l-arginine.

Currently near-infrared (NIR) luminescence of lanthanide ions has received great attention because of their unique emissions in the near-infrared region (800-1700 nm). These NIR luminescent materials behave excellent applications in many fields such as sensors and probes in optical amplification, laser systems, biological systems and organic light-emitting diodes. In this work, two new near-infrared (NIR) emission three-dimensional (3D) YbIII and NdIII cluster-based coordination materials, namely {[Yb2(L)2(DMF)(H2O)4]·(DMF)2 (H2O)}n (NIR-MOF 1) and [Nd(L)(DMF)2]n (NIR-MOF 2) (H3L = terphenyl-3,4″,5-tricarboxylic acid) have been synthesized through the facile sono-chemical preparation methods. Both the near-infrared materials 1 and 2 have been characterized by single crystal X-ray diffraction, powder X-ray diffraction (PXRD) and scanning electron microscopy (SEM). Further the mixed-lanthanide near-infrared emission material Nd0.35Yb0.65L (NIR-MOF 3) can also be prepared under the sono-chemical conditions. NIR-MOF 3 can be successfully applied as the ratiometric NIR-MOF-based thermometer, which should origin from the emission intensity ratio between Yb3+ (976 nm) and Nd3+ (1056 nm) in the temperature range of 308-348 K. Besides these, the micro-morphologies of NIR-MOF 1 can be deliberately tuned through different sono-chemical reaction factors (reaction time, reaction temperature and sono-chemical powers). These tuned nano-sized materials NIR-MOF 1 (100 W, 80 min) can be utilized as the fluorescent sensing material to distinguish furazolidone and sulfasalazine from other antibiotics. At the same time, NIR-MOF 2 can be applied as the first example of MOFs-based sensors for discriminating l-arginine from other amino acids through the "turn-on" mode in the near-infrared emission region.

Highly sensitive furazolidone monitoring in milk by a signal amplified lateral flow assay based on magnetite nanoparticles labeled dual-probe.

We presented a signal amplified lateral flow assay (LFA) based on magnetite nanoparticles (MNPs) labeled dual-probe and applied it in the high sensitive and rapid on-site detection of furazolidone metabolite of 3-amino-2-oxazolidinone (AOZ). The amplified signal benefited from high affinity between two probes of MNPs labeled murine monoclonal antibody (MNPs-MAb) and goat anti-mouse antibody (MNPs-GAMA) and was achieved by the generation of dual-probe network complex. This developed method could realize high sensitive detection of AOZ with a threshold value of 0.88 ng mL-1 and a detection limit of 0.044 ng mL-1, the sensitivity was at least 10-fold improved than that of the traditional gold nanoparticle based LFA. This facile developed assay was successfully applied for rapid detection of AOZ in milk samples. The proposed method paves a new way for on-site screening of other hazardous substances in food and can be referred in all lateral flow assays.

[Antimicrobial activity of core-sheath surgical sutures modified with poly-3-hydroxybutyrate].

To impart antimicrobial activity to surgical sutures, weaved polyester fibers are coated with poly-3-hydroxybutyrate (PHB), containing the antimicrobial agent furazolidone (FZ). The prolonged FZ effect (7-14 days) is achieved by two-step application of a sheath, constituting 10% of the suture weight and containing 2-6% FZ. The sheath structure and antimicrobial activity of sutures can be modified by the introduction of other biocompatible and biodegradable polymers.

Formulation and advantages of furazolidone in liposomal drug delivery systems.

Furazolidone has proven to have antiprotozoal and antibacterial activity. A number of literature supported its use against Helicobacter pylori. This potential application opens new prospects of its use in clinical settings in triple therapy. In order to avoid side effects associated with this drug, liposomal mucoadhesive drug delivery that can work locally in stomach is considered as an appropriate approach. This study is a focus on formulations and in vitro characterization of liposomes containing furazolidone. Therefore, the effects of variable amounts of drug and cholesterol on encapsulation efficacy and in vitro drug release were evaluated for different liposomal formulations. Mucoadhesive behavior of chitosan coated liposomal at two different pHs was also evaluated and increase in pH from 1.3 to 4.5 increased mucoadhesion from 42% to 60% respectively. Increasing the amount of drug from 4mg to 5mg increased encapsulation activity however, increasing the drug any further decreased encapsulation activity. In contrast, by increasing the amount of cholesterol decrease in encapsulation activity was observed. The optimized formulation with 5mg of drug and 53mg of cholesterol in formulation gave 57% drug release at pH 1.3 but release was increased up to 71% by increasing pH to 4.5 for same amount of drug. However, by using 10.6mg of cholesterol and 5mg of drug the overall release was increased at both pH conditions, at pH 1.3 release was 69% as compared to 77% at pH 4.5. This trend of drug release profile and mucoadhesion that favors pH 4.5 is documented as useful in targeting H. pylori as normal pH of stomach is expected to be higher by the influence of this microbe. Hence, the results of this research can be taken further into a future in vivo study.

Bioactive polymers 68--controlled release of neomycin-furazolidone bicomponent system from xanthan hydrogel.

The neomycin-furazolidone-xanthan complex has been synthesized. Neomycin is covalently linked to xanthan, while furazolidone is inserted in the hydrogel formed by the reaction between neomycin and xanthan. The content of neomycin and furazolidone depends on the drug rate in the reaction medium. Thus, a zero-order kinetics is obtained for the release of both neomycin and furazolidone in basic medium. The complex's antimicrobial activity is intensified.

Stability-indicating first-derivative spectrophotometric determination of furazolidone.

A first derivative (1D) spectrophotometric method is described for the determination of furazolidone in the presence of its degradation product (5-nitrofuraldehyde). The method was based on the direct measurement at the maximum of the first derivative curve for furazolidone at 390 nm, which is the zero crossing point of 5-nitrofuraldehyde thus avoiding interference from the degradation product. 5-Nitrofuraldehyde was determined after thin-layer chromatographic separation using silica gel G254 as the coating substance, and mixture of toluene and 1.4-dioxan (95:5) as the developing system. After separation, furazolidone content and its degradation product, 5-nitrofuraldehyde, could be determined separately by first-derivative spectrophotometry at 390 and 290 nm, respectively. 2.5-25 micrograms ml-1 of furazolidone and 5-nitrofuraldehyde could be determined by this method with good accuracy. The proposed method was successfully applied to determine furazolidone in its tablets and 5-nitrofuraldehyde in expired tablets. The results obtained were in good agreement with those obtained by the official method.

Electrochemistry of the interaction of furazolidone and bovine serum albumin.

The electrochemical behavior of the interaction of furazolidone (Fu) with bovine serum albumin (BSA) was investigated by cyclic voltammetry and differential pulse voltammetry at a glassy carbon electrode. Fu shows an irreversible reduction at -0.34 V in pH 4.0 Britton-Robinson buffer (B-R) buffer-10% DMF solution. After the addition of BSA into the Fu solution, the reductive peak currents decreased without any significant shift of the peak potential and the appearance of new peaks. The electrochemical parameters of the interaction system were calculated in the absence and presence of BSA. This electrochemical method was further applied to the determination of BSA samples and the results were in good agreement with the traditional cellulose acetate electrophoresis. The linear dynamic range was between 10.0 and 80.0 mg l(-1). The detection limit was 7.6 mg l(-1) and the recoveries were obtained from 97.0% to 104.0%.

Chemical fate and changes in mutagenic activity of antibiotics nitrofurazone and furazolidone during aqueous chlorination.

Reactions of nitrofuran antibiotics (nitrofurazone (NFZ) and frazolidone (FZD)) with hypochlorite in aqueous solution were investigated under the conditions that simulate wastewater disinfection. The chlorination byproducts were determined by high performance liquid chromatography. At the levels of 5 microM, NFZ reacted rapidly with free chlorine in neutral pH (7.0), while the FZD-hypochlorite reaction was reasonably slow under the same pH. Nevertheless, the strong mutagenic parents disappeared completely after the hypochlorite reactions, and the chlorination byproducts were observed to exert a weak mutagenic effect on Salmonella typhimurium TA100 without S9-mix. The extent of the reactions depended on the chlorine dose, solution pH and compound structures.

Electrochemical studies of nitroheterocyclic compounds of biological interest. VII. Effect of electrode material.

The electrochemical behaviour of three nitrofuran compounds, nitrofurazone, nitrofurantoin and furazolidone, has been studied in three solvent types; aprotic, aqueous and mixed, and at four working electrodes. Particular attention has focused on the 1-electron RNO2/RNO2.- couple as measured by the cyclic voltammetric mode. Using Hg in aqueous buffer, reduction of the NO2 group proceeds directly to the hydroxylamine with no intermediate stages being identified. Addition of an aprotic solvent gave a 2-stage reduction, initially forming the RNO2.- species. At all solid electrodes, however, the RNO2/RNO2.- couple was identified under simple aqueous conditions. The switch to a mixed aqueous/aprotic solvent medium produced only minor changes in the response compared with the situation on Hg. This presents the opportunity of using nitrofuran complexes as model systems for the redox behaviour of nitro aromatic compounds in general at solid electrode surfaces where the latters' more negative reduction potentials makes direct study difficult. The conditions have been defined whereby we can examine pH effects and RNO2.- biological target interactions in simple aqueous media to allow the further refinement of the electrolytic model system for studying bio-reducible drug action.

Studies on antipeptic ulcer agents: a structure-activity relationship analysis of aldehyde semicarbazones and aryl hydrazones.

Twenty-eight condensation products of heterocyclic-a-carboaldehydes with N-aminooxazolidones, semicarbazides, thiosemicarbazides and benzoxycarbonyl hydrazide were synthesized so as to deduce the antiulcer pharmacophore or fragment of furazolidone (I), a prototype which has shown therapeutic efficacy in patients with gastric and duodenal ulcers. SAR analysis of the compounds indicated that the substitution of furan, thiophene, pyrrole or N-methyl pyrrole rings for 5-nitrofuran and the cleavage of the oxazolidone ring did not fully destroy the activity. The electron density of the carbonyl group was found to be of importance. A lead structure, therefore, was derived for further optimization.

Determination of furazolidone in porcine tissue using thermospray liquid chromatography-mass spectrometry and a study of the pharmacokinetics and stability of its residues.

A method is presented for the detection of the nitrofuran, furazolidone, in porcine tissue. Following methanol-buffer extraction of the tissue, liquid partitioning, and solid-phase clean-up, samples are analysed by using thermospray LC-MS monitoring the positive ion m/z 243 with filament-assisted ionization. The LOD is 1 microgram kg-1. The assay is used to investigate the depletion of furazolidone from tissue and sample stability post mortem. It is necessary to snap-freeze samples by immersion in liquid nitrogen immediately upon collection in order to improve the stability of residues in tissue.