A novel ratiometric electrochemical sensing platform combined with molecularly imprinted polymer and Fe-MOF-NH2/CNTs-NH2/MXene composite for efficient detection of ofloxacin.

BACKGROUND: Ofloxacin (OFL) is often abused in medicine and animal husbandry, which poses a great threat to human health and ecological environment. Therefore, it is necessary to establish efficient method to detect OFL. Electrochemical sensor has attracted widespread attention due to the advantages of low cost and fast response. However, most electrochemical sensors usually use one response signal to detect the target, which makes it sensitive to the variable background noise in the complex environment, resulting in low robustness and selectivity. The ratio detection mode and employing molecularly imprinted polymer (MIP) are two strategies to solve these problems. RESULTS: A novel molecular imprinting polymer-ratiometric electrochemical sensor (MIP-RECS) based on Fe-MOF-NH2/CNTs-NH2/MXene composite was prepared for the rapid and sensitive detection of OFL. The positively charged Fe-MOF-NH2 and CNTs-NH2 as interlayer spacers were introduced into the negatively charged MXene through a simple electrostatic self-assembly technique, which effectively prevented the agglomeration of MXene and increased the electrocatalytic activity. A glass carbon electrode was modified by the composite and a MIP film was electropolymerized on it using o-phenylenediamine and ß-cyclodextrin as bifunctional monomers and OFL as template. Then a MIP-RECS was designed by adding dopamine (DA) into the electrolyte solution as internal reference, and OFL was quantified by the response current ratio of OFL to DA. The current ratio and the concentration of OFL displayed a satisfying linear relationship in the range of 0.1 µM-100 µM, with a limit of detection (LOD) of 13.2 nM. SIGNIFICANCE: Combining molecular imprinting strategy and ratio strategy, the MIP-RECS has impressive selectivity compared with the non-imprinted polymer-RECS, and has better repeatability and reproducibility than non-ratiometric sensor. The MIP-RECS has high sensitivity and accuracy, which was applied for the detection of OFL in four different brands of milk and was verified by HPLC method with satisfactory results.

Efficacy and tolerability of a 4-month ofloxacin-containing regimen compared to a 6-month regimen in the treatment of patients with superficial lymph node tuberculosis: a randomized trial.

BACKGROUND: Tuberculosis (TB) lymphadenitis is the most common form of extra-pulmonary TB, and the treatment duration is six months. This non-inferiority based randomized clinical trial in South India evaluated the efficacy and safety of a four-month ofloxacin containing regimen in tuberculosis lymphadenitis (TBL) patients. METHODS: New, adult, HIV-negative, microbiologically and or histopathologically confirmed superficial lymph node TB patients were randomized to either four-month oflaxacin containing test regimen [ofloxacin (O), isoniazid (H), rifampicin (R), pyrazinamide (Z) -2RHZO daily/ 2RHO thrice-weekly] or a six-month thrice-weekly control regimen (2HRZ, ethambutol/4RH). The treatment was directly observed. Clinical progress was monitored monthly during and up to 12 months post-treatment, and thereafter every three months up to 24 months. The primary outcome was determined by response at the end of treatment and TB recurrence during the 24 months post-treatment. RESULTS: Of the 302 patients randomized, 298 (98.7%) were eligible for modified intention-to-treat (ITT) analysis and 294 (97%) for per-protocol (PP) analysis. The TB recurrence-free favourable response in the PP analysis was 94.0% (95% CI: 90.1-97.8) and 94.5% (95% CI: 90.8-98.2) in the test and control regimen respectively, while in the ITT analysis, it was 92.7% and 93.2%. The TB recurrence-free favourable response in the test regimen was non-inferior to the control regimen 0.5% (95% CI: -4.8-5.9) in the PP analysis based on the 6% non-inferiority margin. Treatment was modified for drug toxicity in two patients in the test regimen, while one patient had a paradoxical reaction. CONCLUSION: The 4-month ofloxacin containing regimen was found to be non-inferior and as safe as the 6-month thrice-weekly control regimen.

Achilles tendon complications of fluoroquinolone treatment: a molecule-stratified systematic review and meta-analysis.

Purpose: The association between fluoroquinolone intake and Achilles tendinopathy (AT) or Achilles tendon rupture (ATR) is widely documented. However, it is not clear whether different molecules have the same effect on these complications. The purpose of this study was to document Achilles tendon complications for the most prescribed fluoroquinolones molecules. Methods: A literature search was performed on Pubmed, Cochrane, Embase, and Web of Science databases up to April 2023. Inclusion criteria: studies of any level of evidence, written in English, documenting the prevalence of AT/ATR after fluoroquinolone consumption and stratifying the results for each type of molecule. The Downs and Black's 'Checklist for Measuring Quality' was used to evaluate the risk of bias. Results: Twelve studies investigating 439,299 patients were included (59.7% women, 40.3% men, mean age: 53.0 ± 15.6 years). The expected risk of AT/ATR was 0.17% (95% CI: 0.15-0.19, standard error (s.e.): 0.24) for levofloxacin, 0.17% (95% CI: 0.16-0.19, s.e.: 0.20) for ciprofloxacin, 1.40% (95% CI: 0.88-2.03, s.e.: 2.51) for ofloxacin, and 0.31% (95% CI: 0.23-0.40, s.e.: 0.77) for the other molecules. The comparison between groups documented a significantly higher AT/ATR rate in the ofloxacin group (P < 0.0001 for each comparison). Levofloxacin and ciprofloxacin showed the same risk (P = n.s.). The included studies showed an overall good quality. Conclusion: Ofloxacin demonstrated a significantly higher rate of AT/ATR complications in the adult population, while levofloxacin and ciprofloxacin showed a safer profile compared to all the other molecules. More data are needed to identify other patient and treatment-related factors influencing the risk of musculoskeletal complications.

The Effect of Using Ofloxacin Ear Drops in Traumatic Tympanic Membrane Healing: A Systematic Review and Meta-Analysis.

Objectives: To evaluate the effectiveness of ofloxacin ear drops versus no intervention in the repair of traumatic tympanic membrane (TM) perforations from randomized controlled trials (RCTs). Data Sources: Medline/PubMed, CENTRAL, Clinical Trials.Gov, and Google Scholar. Study Selection: Inclusion criteria: (1) English language; (2) RCT studies; (3) reported the outcomes on the application of ofloxacin and outcomes of spontaneous healing. Exclusion criteria: (1) studies without a control group; (2) patient with severe otologic disease such as chronic suppurative otitis media or ossicular disruption or patients with craniocerebral injury; (3) studies with no pretreatment values or single-arm clinical studies. Data Extraction: Country, year of publication, number of participants in each arm, patient characteristics such as age, sex, intervention details, laterality, cause of TM perforation, position of perforation, follow-up time, hearing gain, rate of TM closure, and closure time. Results: A total of 6 RCTs studies were analyzed. A total of 502 participants were included; the relative risk for closure rate of ofloxacin treatment was 1.18 [95% confidence interval (CI), 1.08 to 1.28, P < .001] and the mean difference (MD) for healing time was -18.4 (95% CI, -19.96 to -16.82, P < .001), suggesting ofloxacin has a significant effect on closure of TM perforations. However, no clinically significant effect in hearing (SMD: 0.21, 95% CI, 0.02 to 0.40, P = .03) was seen in ofloxacin group. Also, patients in the ofloxacin group were associated with a 13% reduction in the risk of infections compared to their observation-assigned counterparts, but this estimate was not statistically significant. Conclusion: Ofloxacin use in patients with traumatic TM perforation is effective in reducing healing time and increasing rate of TM perforation closure. No evidence of increased risk of hearing loss or infection rates are encountered when ofloxacin is prescribed to patients with traumatic TM perforation.

Dual role of dissolved black carbon in sensitized ofloxacin photooxidation: Mechanism and influential factors.

Dissolved black carbon (DBC) is the more photoactive component of dissolved organic matter (DOM) pool, which plays a dual role in the photoconversion of aquatic contaminants, acting as both a photosensitizer and an inhibitor. However, little is known about the more systematic mechanism by which DBC exhibits a dual effect, which is closely related to the structure composition of DBC. In this study, the differences in characteristics of DBC obtained from 300 °C and 500 °C were compared via UV-vis absorption spectrum, Fluorescence excitation emission matrix spectra (3D-EEM), Fourier transform infrared (FT-IR), and X-ray photoelectron spectroscopy (XPS), and evaluated the promoting and inhibiting effects of DBC on ofloxacin (OFL) photodegradation. It was found that higher pyrolysis temperature reduced the UV absorbance, molecular weight, aromaticity, and phenolics of DBC while increasing the content of quinone/aromatic ketone and humic substances. Photochemical data showed that 3DBC*, 1O2 and ·OH were all participated in the DBC-mediated OFL photodegradation. Wherein, DBC300 (DBCT, where T = pyrolysis temperature) had strong light screening and dynamic quenching effect, but the formation ability of 3DBC*, 1O2 and ·OH was poor, which significantly retarded the photodegradation of OFL. While DBC500 exhibited a slight promotion effect due to its higher formation ability of reactive species and weak light screening effect. Moreover, DBC500 had higher steady-state concentration and (kOFL,3DBC⁎) than DBC300, which might be due to the higher contents of quinone/aromatic ketone and the lower contents of phenol in DBC500, thus enhancing the reactivity of 3DBC* and OFL. Our research systematically revealed the trade-off mechanism of DBC on the photodegradation of fluoroquinolones, and provided an important theoretical guidance for the photodegradation of fluoroquinolones under the evolution of DBC composition.

Photo-transformation of ofloxacin in natural aquatic conditions: Impact of indirect photolysis on the product profile and transformation mechanism.

The natural phototransformation of organic pollutants in the environment depends on several water constituents, including inorganic ions, humic substances, and pH. However, the literature information concerning the influence of various water components on the amount of phototransformation and their impact on the development of various transformation products (TPs) is minimal. This study investigated the phototransformation of ofloxacin (OFL), a fluoroquinolone antibiotic, in the presence of various water components such as cations (K+, Na+, Ca2+, NH4+, Mg2+), anions (NO3-, SO42-, HCO3-, CO32-, PO43-), pH, and humic substances when exposed to natural sunlight. The study reveals that neutral pH levels (0.39374 min⁻1) enhance the phototransformation of OFL in aquatic environments. Carbonate, among anions, shows the highest rate constant (2.89966 min⁻1), significantly influencing OFL phototransformation, while all anions exhibit a notable impact. In aquatic environments, indirect phototransformation of OFL, driven by increased reactive oxygen species, expedites light-induced reactions, potentially enhancing OFL phototransformation. A clear difference was visible in the type of transformation products (TPs) formed during direct and indirect photolysis. The impact of indirect photolysis in the product profile was evaluated by examining the unique properties of TPs in direct and indirect photolysis. The primary transformation products were generated by oxidation and cleavage processes directed towards the ofloxacin piperazinyl, oxazine, and carboxyl groups. The toxicity assessment of TPs derived from OFL revealed that among the 26 identified TPs, TP3 (demethylated product), TP7 and TP8 (decarboxylated products), and TP15 (piperazine ring cleaved product) could potentially have some toxicological effects. These findings suggest that the phototransformation of OFL in the presence of various water components is necessary when assessing this antibiotic's environmental fate.

The resistance of hydrogenotrophic methanogenic microorganisms to ofloxacin in sludge anaerobic digestion process.

Ofloxacin (OFL) is a commonly used antibiotic that can enter wastewater treatment plants and be adsorbed by the sludge, resulting in a high OFL concentration in sludge and affecting the subsequent sludge anaerobic digestion process. However, the micro mechanisms involved in this process have not been thoroughly studied. Therefore, this study focuses on the effect of OFL on the sludge anaerobic digestion of sludge to provide such support. The experimental results showed that the maximal methane yield decreased from 277.7 to 164.7 mL/g VSS with the OFL concentration increased from 0 to 300 mg/L. Additionally, OFL hindered the intermediate biochemical processes of hydrolysis, acidogenesis, acetogenesis, and acetoclastic methanogenesis. However, it promoted hydrogenotrophic methanogenesis process, using H2 as substrate, with the concentration of 300 mg/L OFL was 5.54 fold methane production of that in the control. Further investigation revealed that the negative effect of OFL was likely due to the induction of reactive oxygen species, which led to a decrease in cell activity and interference with the activity of key enzymes. Microbiological analysis revealed that OFL reduced the relative abundance of hydrolysis and acidogenesis bacteria, and Methanosaeta archaea, while increasing the relative abundance of hydrogenotrophic methanogenesis microorganism from 36.54% to 51.48% as the OFL concentration increase from 0 to 300 mg/L.

Combining GC-MS/MS with a LLE-SPE sample pretreatment step to simultaneously analyse enrofloxacin and ofloxacin residues in chicken tissues and pork.

A widely applicable original gas chromatography-tandem mass spectrometry (GC-MS/MS) method was explored to qualitatively and quantitatively measure enrofloxacin and ofloxacin residues in chicken tissues and pork. The experimental samples were processed based on liquid-liquid extraction (LLE) and solid-phase extraction (SPE). Trimethylsilyl diazomethane (TMSD) was chosen to react derivatively with enrofloxacin and ofloxacin. In total, 78.25% âˆ¼ 90.56% enrofloxacin and 78.43% âˆ¼ 91.86% ofloxacin was recovered from the blank fortified samples. The limits of detection (LODs) were 0.7-1.0 µg/kg and 0.1-0.2 µg/kg, respectively. The limits of quantitation (LOQs) were 1.6-1.9 µg/kg and 0.3-0.4 µg/kg, respectively. It was verified that various experimental data met the requirements of the FAO & WHO (2014) for the detection of veterinary drug residues. Real samples obtained from local markets were analysed using the established method, and no residues of enrofloxacin or ofloxacin were detected in the samples.

A challenging case of borderline lepromatous leprosy non-responsive to WHO-MDT: exploring approaches beyond WHO-MDT.

Just as we prioritize personalized medicine for various other medical conditions, we should also include a neglected disease like leprosy, ensuring that patients receive the best care possible and improving their quality of life. Our case highlights the importance of instituting an alternate therapeutic regimen in a scenario where there is a lack of clinical response to multidrug therapy, even in the absence of documented drug resistance of the currently available molecular diagnostics. The search for the perfect regimen tailored for each individual leprosy patient should continue. Alternate anti-leprosy therapy is highly useful in cases with confirmed drug resistance or clinically non-responsive cases; however, their misuse should also be strictly avoided to prevent the development of resistance to them.

Construction and regulation of high active sites in montmorillonite composite catalyst for the removal of ofloxacin via persulfate activation.

In this study, ionic liquids (ILs) were used as organic modifiers by introducing montmorillonite nanolayers containing potential C and N active sites between the montmorillonite nanolayers. Organically modified montmorillonite (ILs-Mt-p) was further prepared by high-temperature pyrolysis under N2 and used for the removal of ofloxacin (OFL) by activated peroxymonosulfate (PMS). Combined with XPS and other characterization analyses, it was found that the catalyst materials prepared from different organic modifiers had similar surface functional groups and graphitized structures, but contained differences in the types and numbers of C and N active sites. The catalyst (3CPC-Mt-p) obtained after pyrolysis of montmorillonite modified with cetylpyridinium chloride (CPC) had optimal catalytic performance, in which graphitic C, graphitic N, and carbonyl group (C[bond, double bond]O) could synergistically promote the activation of PMS by electron transfer, and 77.3 % of OFL could be removed within 60 min. The effects of OFL concentration, initial pH, and anions on the effects of OFL removal by the 3CPC-Mt-p/PMS system were further investigated. Satisfactory degradation results were obtained over a wide pH range. Cl- promoted the system to degrade OFL, while the presence of SO42-, H2PO4- and HA showed some inhibition, but overall the 3CPC-Mt-p catalysts had a strong anti-interference ability, showing good application prospects. The quenching experiments and EPR tests showed that O2-- and 1O2 in the 3CPC-Mt-p/PMS system were the main reactive oxygen species for the degradation of OFL, and •OH was also involved in the reaction. This study provides ideas for the construction and modulation of active sites in mineral materials such as montmorillonite and broadens the application of montmorillonite composite catalysts in advanced oxidation processes for the treatment of antibiotic wastewater.

Sphere-shaped ZnO photocatalyst synthesis for enhanced degradation of the Quinolone antibiotic, Ofloxacin, under UV irradiation.

The sphere-shaped zinc oxide (ZnO) photocatalyst was synthesized by the homogeneous precipitation method, using Zn(CH3COO)2·2H2O as a zinc precursor and NH4OH as a precipitating agent. The morphology and crystal structure of the prepared ZnO sample were studied by XRD, SEM, FT-IR, XPS, zeta potential measurements, and a low-temperature nitrogen adsorption-desorption technique. The optical characteristics of ZnO were determined by UV - Vis diffuse reflectance spectroscopy. ZnO photocatalyst performance of up to 100% within 210 min was observed in the photodegradation of the ofloxacin antibiotic under ultraviolet (UV) irradiation. The effect of antibiotic concentration, heavy metal ions, and water sources on the photocatalytic activity of ZnO demonstrated both the potential of its application under different conditions, and a good adaptability of this photocatalyst. The photodegradation reaction correlated well with the first-order kinetics model, with a rate constant of 0.0173 min-1. The reusability of the photocatalyst was verified after three cycles of use. Admittedly, photogenerated electrons and holes played a key role in removal of the antibiotic. This work showed the suitability of prepared ZnO for antibiotic removal, and its potential use for environmental protection.

Distribution of Fluoroquinolone-Resistant Escherichia coli in Parent Flocks Treated with Fluoroquinolones on Chick Stage and their Broiler Offspring.

This study investigated the distribution of ofloxacin-resistant Escherichia coli (OFXR-EC) in broiler parent flocks (PS) treated with ofloxacin for 5 days from the time the chicks arrived at the poultry house, and their broiler offspring. OFXR-EC was detected in 22.95% of neonatal parent stock chicks (PSN) arriving at the poultry house. The detection rate of OFXR-EC in PS rearing was 72.49%, which was significantly higher than that detected in PSN. In addition, the detection rate of OFXR-EC was significantly lower in neonatal chicks of their offspring broilers (CSN) at 7.06% than that of PS, but was 24.62% in offspring broiler flocks (CS) at approximately 6 weeks of age. The OFXR-EC detection rate was significantly higher in CS than that in CSN, even though no therapeutic antimicrobials, including ofloxacin, were used from CSN to CS. In addition, the proportions of OFXR-ECs in E. coli isolated from samples in which OFXR-ECs were detected were 63.85% for PSN, 10.52% for PS, 62.00% for CSN, and 8.25% for CS. There was little difference in the composition ratio of OFXR-EC between PSN and CSN, or between PS and CS.

Cu2MoS4 Nanocatalyst-Based Electrochemical Sensor for Ofloxacin Electro-Oxidation: Delineating the Combined Roles of Crystallinity and Morphology on the Analytical Performance.

In this study, we demonstrate the influence of crystallinity and morphology on the analytical performance of various Cu2MoS4 (CMS) nanocatalysts-based electrochemical sensors for the high-efficiency detection of Ofloxacin (OFX) antibiotic. The electrochemical kinetics parameters including peak current response (ΔIp), peak-to-peak separation (ΔEp), electrochemically active surface area (ECSA), electron-transfer resistance (Rct), were obtained through the electrochemical analyses, which indicate the single-crystalline nature of CMS nanomaterials (NMs) is beneficial for enhanced electron-transfer kinetics. The morphological features and the electrochemical results for OFX detection substantiate that by tuning the tube-like to plate-like structures of the CMS NMs, it might noticeably enhance multiple adsorption sites and more intrinsic active catalytic sites due to the diffusion of analytes into the interstitial spaces between CMS nanoplates. As results, highly single-crystalline and plate-shaped morphology structures of CMS NMs would significantly enhance the electrocatalytic OFX oxidation in terms of onset potential (Eonset), Tafel slope, catalytic rate constant (kcat), and adsorption capacity (Γ). The CMS NMs-based electrochemical sensing platform showed excellent analytical performance toward the OFX detection with two ultra-wide linear detection concentration ranges from 0.25-100 and 100-1000 µM, a low detection limit of 0.058 µM, and an excellent electrochemical sensitivity (0.743 µA µM-1 cm-2).

Aptamer-Based Sensor for Rapid and Sensitive Detection of Ofloxacin in Meat Products.

Ofloxacin (OFL) is widely used in animal husbandry and aquaculture due to its low price and broad spectrum of bacterial inhibition, etc. However, it is difficult to degrade and is retained in animal-derived food products, which are hazardous to human health. In this study, a simple and efficient method was developed for the detection of OFL residues in meat products. OFL coupled with amino magnetic beads by an amination reaction was used as a stationary phase. Aptamer AWO-06, which showed high affinity and specificity for OFL, was screened using the exponential enrichment (SELEX) technique. A fluorescent biosensor was developed by using AWO-06 as a probe and graphene oxide (GO) as a quencher. The OFL detection results could be obtained within 6 min. The linear range was observed in the range of 10-300 nM of the OFL concentration, and the limit of the detection of the sensor was 0.61 nM. Furthermore, the biosensor was stored at room temperature for more than 2 months, and its performance did not change. The developed biosensor in this study is easy to operate and rapid in response, and it is suitable for on-site detection. This study provided a novel method for the detection of OFL residues in meat products.

Adverse reactions induced by MDT/WHO (Rifampicin+Clofazimine+Dapsone) and ROM (Rifampicin+Ofloxacin+Minocycline) regimens used in the treatment of leprosy: a cohort study in a National Reference Center in Brazil.

Background: Recommended standard treatment for leprosy is multidrugtherapy (MDT/WHO), consisting Rifampicin+Dapsone+Clofazimine. Other medications are recommended in cases of resistance, adverse reactions and intolerances, including ROM regimen, Rifampicin+Ofloxacin+Minocycline. Therefore, pharmacovigilance is an important tool in understanding these adverse drug reactions (ADRs), supporting pharmacotherapy management and medication safety. This study seeks to evaluate ADRs comparing two therapeutic regimens, MDT and ROM, used in treatment of patients with leprosy, analyzing prognostic factors regarding risk and safety. Methods:A retrospective cohort study was performed by assessing medical records of 433 patients diagnosed with leprosy from 2010 to 2021 at a National Reference Center in Brazil. They were subject to 24 months or more of treatment with MDT or ROM regimens. ADR assessments were analyzed by two experienced researchers, who included clinical and laboratory variables, correlating them with temporality, severity and the causality criteria of Naranjo and WHO. Results: The findings observed an average of 1.3 reactions/patient. Out of individuals experiencing reactions, 67.0% (69/103) were utilizing MDT/MB, while 33.0% (34/103) were using ROM. The median time for ADR of 79 days for MDT and 179 days for ROM. In first reaction, Dapsone was the most frequently involved medication; the most affected system was hematopoietic. As compared to Clofazimine, results indicated that use of Dapsone was associated with 7% increased risk of ADR occurrence (HR: 1.07; p = 0.866). Additionally, Rifampicin was linked to 31% increased risk of ADRs (HR: 1.31; p = 0.602); and Ofloxacin showed 35% elevated risk (HR: 1.35; p = 0.653). Conversely, results for Minocycline indicated 44% reduction in the risk of ADRs (HR: 0.56; p = 0.527), although statistical significance was not reached. The use of MDT conferred 2.51 times higher risk of developing ADRs in comparison to ROM. Conclusion: The comparison between MDT and ROM revealed that MDT caused more ADRs, and these reactions were more severe, indicating less safety for patients. Dapsone was the most common medication causing ADRs, followed by Rifampicin. The combination with Clofazimine was associated with an additional risk of ADRs, warranting further studies to confirm this hypothesis. Given the high magnitude of ADRs, healthcare teams need to monitor patients undergoing leprosy treatment with focus on pharmacovigilance.

A Case of Anaphylactic Shock Due to Levofloxacin Eye Drops Confirmed by a Prick Test.

Topical levofloxacin has been used safely, but it can induce life-threatening hypersensitivities. We report a case of anaphylactic shock caused by levofloxacin eye drops during the treatment of a corneal injury, confirmed by a prick test. Reported cases of hypersensitivity to levofloxacin and its racemate ofloxacin eye drops are also summarized.

Simultaneous identification and enantioseparation of ofloxacin and duloxetine without the single standard and computational calculation of their inclusion complexes.

Given the markedly different pharmacological activities between enantiomeric isomers, it is crucial to encourage the stereoselective determination of chiral drugs in the biological and pharmaceutical fields, and the combination of drugs makes this analysis more complicated and challenging. Herein, a capillary electrophoresis (CE) method for the enantioseparation of ofloxacin and duloxetine was established, enabling the simultaneous identification of four isomers in nonracemic mixtures with enantiomeric excess (ee%) values exceeding 5%. This was achieved through the integration of theoretical simulation and electron circular dichroism (ECD), all without reliance on individual standards. Molecular modeling explained and verified the migration time differences of these isomers in electrophoretic separation. Moreover, the correlation coefficients (R2 ) between the enantiomeric peak area differentials and ee% were both above 0.99. Recovery rates were quantified using bovine serum as the matrix, with results ranging from 93.32% to 101.03% (RSD = 0.030) and 92.69% to 100.52% (RSD = 0.028) for these two chiral drugs at an ee value of 23.1%, respectively.

Adsorption, natural attenuation, and microbial community response of ofloxacin and oxolinic acid in marine sediments.

The pollution of quinolone antibiotics in the marine environment has attracted widespread attention, especially for ofloxacin (OFL) and oxolinic acid (OXO) due to their frequent detection. However, few studies have been conducted to assess the behaviors and microbial community response to these antibiotics in marine sediments, particularly for potential antibiotic-resistant bacteria. In this work, the adsorption characteristics, natural attenuation characteristics, and variation of microbial communities of OFL and OXO in marine sediments were investigated. The adsorption process of antibiotics in sediments occurred on the surface and internal pores of organic matter, where OFL was more likely to be transferred from seawater to sediment compared with OXO. Besides, the adsorption of two antibiotics on sediment surfaces was attributed to physisorption (pore filling, electrostatic interaction) and chemisorption (hydrogen bonding). The natural attenuation of OFL and OXO in marine sediment followed second-order reaction kinetics with half-lives of 6.02 and 26.71 days, respectively, wherein biodegradation contributed the most to attenuation, followed by photolysis. Microbial community structure in marine sediments exposure to antibiotics varied by reducing abundance and diversity of microbial communities, as a whole displaying as an increase in the relative abundance of Firmicutes whereas a decrease of Proteobacteria. In detail, Escherichia-Shigella sp., Blautia sp., Bifidobacterium sp., and Bacillus sp. were those antibiotic-resistant bacteria with potential ability to degrade OFL, while Bacillus sp. may be resistant to OXO. Furthermore, functional predictions indicated that the microbial communities in sediment may resist the stress caused by OFL and OXO through cyano-amino acid metabolism, and ascorbate and aldarate metabolism, respectively. The research is key to understanding fate and bacterial resistance of antibiotics in marine sediments.

A direct electrochemical sensor based on covalent organic frameworks/platinum nanoparticles for the detection of ofloxacin in water.

A direct electrochemical sensor based on covalent organic frameworks (COFs)/platinum nanoparticles (PtNPs) composite was fabricated for the detection of ofloxacin (OFX) in water. Firstly, the COF material was synthesized via the condensation reaction of 1,3,5-tris(4-aminophenyl)benzene (TAPB) with terephthalaldehyde (TPA) and integrated with PtNPs by in situ reduction. Then, TAPB-TPA-COFs/PtNPs composite was loaded onto the surface of the glassy carbon electrode (GCE) by drip coating to construct the working electrode (TAPB-TPA-COFs/PtNPs/GCE). The electrochemical performance of TAPB-TPA-COFs/PtNPs/GCE showed a significant improvement compared with that of TAPB-TPA-COFs/GCE, leading to a 3.2-fold increase in the electrochemical signal for 0.01 mM OFX. Under optimal conditions, the TAPB-TPA-COFs/PtNPs/GCE exhibited a wide linear range of 9.901 × 10-3-1.406 µM and 2.024-15.19 µM with a detection limit of 2.184 × 10-3 µM. The TAPB-TPA-COFs/PtNPs/GCE-based electrochemical sensor with excellent performance provides great potential for the rapid and trace detection of residual OFX.

Dissociation Kinetics and Antimicrobial Activity of Ofloxacin Antibiotic in Artificial Tears Via 1H-NMR, Raman, and UV-Vis Spectroscopic Analysis.

Introduction: The hydrogen-bonded networks play a significant role in influencing several physicochemical properties of ofloxacin in artificial tears (ATs), including density, pH, viscosity, and self-diffusion coefficients. The activities of the ofloxacin antibiotic with Ats mixtures are not solely determined by their concentration but are also influenced by the strength of the hydrogen bonding network which highlight the importance of considering factors such as excessive tear production and dry eye conditions when formulating appropriate dosages of ofloxacin antibiotics for eye drops. Objectives: Investigating the physicochemical properties of ofloxacin-ATs mixtures, which serve as a model for understanding the impact of hydrogen bonding on the antimicrobial activity of ofloxacin antibiotic eye drops. Determine the antimicrobial activities of the ofloxacin-Ats mixture with different concentration of ofloxacin. Methods: The ofloxacin-ATs mixtures were analyzed using 1H-NMR, Raman, and UV-Vis spectroscopies, with variation of ofloxacin concentration to study its dissociation kinetics in ATs, mimicking its behavior in human eye tears. The investigation includes comprehensive analysis of 1H-NMR spectral data, self-diffusion coefficients, Raman spectroscopy, UV-Vis spectroscopy, liquid viscosity, and acidity, providing a comprehensive assessment of the physicochemical properties. Results: Analysis of NMR chemical shifts, linewidths, and self-diffusion coefficient curves reveals distinct patterns, with peaks or minima observed around 0.6 ofloxacin mole fraction dissociated in ATs, indicating a strong correlation with the hydrogen bonding network. Additionally, the pH data exhibits a similar trend to viscosity, suggesting an influence of the hydrogen bonding network on protonic ion concentrations. Antibacterial activity of the ofloxacin-ATs mixtures is evaluated through growth rate analysis against Salmonella typhimurium, considering varying concentrations with mole fractions of 0.1, 0.4, 0.6, 0.8, and 0.9. Conclusions: The antibiotic-ATs mixture with a mole fraction of 0.6 ofloxacin exhibited lower activity compared to mixtures with mole fractions of 0.1 and 0.4, despite its lower concentration. The activities of the mixtures are not solely dependent on concentration but are also influenced by the strength of the hydrogen bonding network. These findings emphasize the importance of considering tear over-secretion and dry eye problems when designing appropriate doses of ofloxacin antibiotics for eye drop formulations.