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A capillary electrochromatography (CEC) synergistic enantioseparation system based on a novel nanomaterial synthesized by chiral molecularly imprinted polymers (CMIPs) and chiral metal organic frameworks (CMOFs) was developed. Compared with CMIPs and CMOFs alone, the enantioseparation performance of ofloxacin (OFL) of the CEC with the novel nanomaterial as stationary phases was greatly improved. CMOFs with chiral recognition ability have synergize with CMIPs to greatly improve the chiral selectivity of the novel stationary phases in CEC. As a proof-of-concept demonstration, a coated capillary column was prepared by a sol–gel method using S-OFL (template), iron-based cyclodextrin MOF (Fe-CD-MOF, a CMOF), 3-aminopropyltriethoxysilane (functional monomer), and tetraethyl orthosilicate (cross-linking agent). Then, the newly constructed CEC system has excellent enantioseparation performance of OFL with a resolution of 3.92. Finally, computerized molecular docking revealed that the difference in the binding ability of Fe-CD-MOF to ofloxacin enantiomers was an important mechanism for CEC chiral separation. This innovative development of synergistic chiral stationary phases based on CMOFs and CMIPs creates a highly efficient potential direction for enantiomer separation. [ABSTRACT FROM AUTHOR]

In situ gels have been developed as an innovative strategy to prolong corneal residence time and enhance drug absorption compared to traditional eye drops. Our study aimed to formulate an ophthalmic in situ gel with a combination of two thermosensitive poloxamers, P407 and P188, in an optimal ratio not only to increase the time of action but also to increase the solubility of selected antibiotics for the treatment of ophthalmic infections. Two BSC II class substances, Azithromycin and Ofloxacin, with different mechanisms of action, have been incorporated into the in situ gel system after determining their solubility. The antibiotics-loaded in situ gel formulation was evaluated for its clarity, pH, rheological properties, and gel characteristics of gelling time, temperature, and capacity. The formulation demonstrated satisfactory clarity, appropriate pH, effective gelation properties in simulated tear fluid, and suitable rheological characteristics. In addition, APIs release insight has been studied through a dissolution test, and the effectivity against sensitive and resistant bacterial strains has been proved through the antimicrobial study. Therefore, our in situ gel system based on thermosensitive poloxamers, with two hydrophobic antibiotics, AZM and OFX, can be considered a valuable approach for ophthalmic drug delivery with an enhancement of the antibiotics bioavailability through increasing the contact time with the ocular surface and enhancing patient compliance. [ABSTRACT FROM AUTHOR]

Introduction: Soil organic matter plays an important role in the long-term "locking" of organic contaminants in soil environment. Recently, microbialderived organic matter have been recognized as essential components of stabilized soil carbon pools. However, the contribution of microbial-derived organic matter to sorption of organic contaminants remains unclear. Methods: Here, we obtained microbial-derived organic matter-mineral composites by inoculating model soil (a mixture of hematite and quartz sand (FQ) or montmorillonite and quartz sand (MQ)) with natural soil microorganisms and different substrate-carbon (glycine (G), glucose (P), or 2, 6-Dimethoxyphenol (B)), which were named GF, PF, BF, GM, BM, and PM, respectively. Batch sorption/ desorption experiments were conducted for phenanthrene (PHE) and ofloxacin (OFL) on the composites. Results and Discussion: The composites cultured with 2,6-dimethoxyphenol had the highest carbon content (0.98% on FQ and 2.11% on MQ) of the three carbon substrates. The carbon content of the composites incubated with MQ (0.64%-- 2.11%) was higher than that with FQ (0.24%--0.98%), indicating that montmorillonite facilitated the accumulation of microbial-derived organic matter owing to its large specific surface area. The sorption of PHE by microbial-derived organic matter was mainly dominated by hydrophobic partitioning and π-π conjugation, whereas the sorption of OFL was mainly dominated by hydrophobic hydrogen bonding and π-π conjugation. The sorption of OFL onto the composites was more stable than that of PHE. Microbial-derived organic matter -mineral composites can reduce the risk of organic contaminant migration in soil, particularly ionic organic contaminants. [ABSTRACT FROM AUTHOR]

Efforts to mitigate the environmental and health risks associated with the antibiotic ofloxacin necessitate innovative methodologies for its detection. The cost of expensive carbon materials like carbon nanofibers can be reduced by making their hybrids with biomass‐derived carbon materials. In this context, a nitrogen‐functionalized carbon nanofiber‐based nanocomposite (N‐LN‐CNF), incorporating activated carbon derived from Lantana Camara, was fabricated for the detection of ofloxacin. X‐ray photoelectron spectroscopy and Fourier Transform Infrared analyses confirmed the presence of nitrogen functionalities in the N‐LN‐CNF. The surface and internal morphology were analyzed using field emission scanning electron microscopy and high‐resolution transmission electron microscopy. The material was tested as an electrochemical sensor for ofloxacin detection. A linear response for ofloxacin was observed in the range of 2 μM to 43 μM for N‐LN‐CNF/GCE via linear sweep voltammetry (LSV) with a limit of detection (LOD) of 1.92 μM. The interaction between the fabricated electrode and the analyte is a combination of diffusion and adsorption‐controlled processes. This metal‐free sensor offers a sustainable approach for detecting ofloxacin in water and pharmaceutical preparations. [ABSTRACT FROM AUTHOR]

This study proposed a novel electrochemical sensor for the sensitive measurement of the eye medication ofloxacin (OFX), which is based on a NiO@C-dot nanocomposite. The NiO@C-dot nanocomposite was synthesized using the sol-gel method, which was then applied to alter a glassy carbon electrode (GCE). With regard to OFX, the modified GCE shown outstanding electrochemical activity along with good sensitivity, selectivity, and stability. With OFX concentrations ranging from 5 µM to 975 µM, the NiO@C-dot/GCE showed a linear relationship with a sensitivity of 0.63994 µA/µM. The limit of detection (LOD) was 0.023 µM. The response to 50 µM OFX was measured, and the electrode was stored at 4°C after each test in order to evaluate the sensor's long-term stability and repeatability. After 20 days, the peak current response was still 97.89 % of its initial value. After 40 days of prolonged storage, 93.78 % of the electrode's original responsiveness was retained. The sensor showed a recovery rate of 97.37–99.70 % in all sample types when it was used to detect OFX in human urine, tap water, and food samples. These findings highlight the NiO@C-dot/GCE's outstanding selectivity, dependability, and longevity as solid platforms for OFX detection in complicated samples for a range of applications. [ABSTRACT FROM AUTHOR]

Background Over the years, reports have associated fluoroquinolones (FQ) with seizures. The incidence and whether FQ compared to non-epileptogenic antibiotic are associated with increased risk of seizures has yet to be examined. Methods A retrospective observational study of hospitalized patients treated with FQ (ofloxacin, ciprofloxacin, levofloxacin, moxifloxacin) or macrolides (MA: azithromycin or roxithromycin) between January 2009 and January 2021 in a large tertiary academic medical centre. The outcome was the occurrence of a seizure during treatment. The Naranjo scale was used to assess causality between FQ treatment and seizures. Comparative analysis was conducted using propensity score matching to correct for possible bias due to non-random selection, followed by inverse probability weighting (IPW) to estimate the difference in seizure risk between FQ and MA. Results Overall, 52 722 patients were treated with FQ during a total of 178 982 days. Mean age was 65 (±19) years and 47% were females. Thirty-three patients (0.06%) experienced a seizure, yielding an incidence of 1:5422 treatment days. Causality was deemed probable and possible among 9/33 and 24/33, respectively. The MA group composed of 8522 patients treated during 17 954 treatment days. Mean age was 65 (±21) years, 49% were females. Six (0.07%) patients experienced each a single seizure. IPW estimated OR for seizures among the FQ versus MA group was 1.44 (95%CI 0.59–3.5, P  = 0.42). Discussion The incidence of FQ associated seizures among hospitalized patients is low and the risk did not significantly exceed that under macrolides. Our results provide evidence for clinicians and decision-makers when balancing fluoroquinolones risks and benefits. [ABSTRACT FROM AUTHOR]

The excessive use of antibiotic ofloxacin (Oflx) can cause serious detrimental effects to human health. Therefore, the utmost research priority is required to develop facile methods to detect Oflx. Herein, a V‐shaped aggregation‐induced emission (AIE) active Schiff base SDANA was introduced for the fluorescent turn‐on detection of Oflx. The Schiff base SDANA was synthesized by condensing 4,4′‐sulfonyldianiline with two equivalents of 2‐hydroxy‐1‐naphthaldehyde. The nearly non‐fluorescent SDANA in DMSO showed strong orange emission with the increase in HEPES buffer (H2O, 10 mM, pH 7.4) fractions in DMSO from 70 %–95 % due to the combined effects of AIE and ESIPT. The DLS and SEM analyses were performed to complement the formation of self‐aggregates of SDANA. With the addition of Oflx, the fluorescence emission of AIE luminogen (AIEgen) SDANA (λem=575 nm, λex=400 nm) was blue‐shifted and enhanced at 530 nm. The interactions of Oflx over the surface of SDANA aggregates disrupted the intramolecular charge transfer and aggregation morphology of SDANA, which gave a distinct fluorescence response to detect Oflx. The detection limit for Oflx was estimated as 0.81 μM, and the developed probe AIEgen SDANA was applied for the quantification of Oflx in human blood serum. [ABSTRACT FROM AUTHOR]

Leprosy remains a significant neglected tropical disease despite the goal of elimination having been achieved in various endemic nations over the past two decades. Reactional episodes complicate the disease course, resulting in deformities and disability. The main aim of treatment is to kill Mycobacterium leprae and decrease the bacterial load, which could help prevent further bacilli transmission. A major concern in breaking the chain of transmission and possibly for recurrent reactions is the role of drug‐resistant bacilli. Though some data is available on the background prevalence of drug resistance in leprosy, there is a paucity of studies that look for resistance specifically in leprosy reactions. Administration of long‐term steroids or immunosuppressants for chronic and recurrent responses in the presence of drug resistance has the twin effect of perpetuating the multiplication of resistant bacilli and encouraging the dissemination of leprosy. The increasing trend of prescribing second‐line drugs for leprosy or type 2 reactions without prior assessment of drug resistance can potentially precipitate a severe public health problem as this can promote the development of resistance to second‐line drugs as well. A comprehensive multicenter study, including drug resistance surveillance testing in cases of reactions, is necessary, along with the current measures to stop the spread of leprosy. Here, we have detailed the history of drug resistance in leprosy, given pointers on when to suspect drug resistance, described the role of resistance in reactions, methods of resistance testing, and the management of resistant cases with second‐line therapy. [ABSTRACT FROM AUTHOR]

Background/Objectives: Bacteria are well known to enter dormancy under stress conditions. However, the mechanisms of different dormancy-related phenotypes are still under debate and many questions remain unanswered. This study aims to better understand the effects of toxin gene expression on the dormancy of Escherichia coli. Methods: The effects of toxin gene expression on growth, persistence, and culturability were characterized. Specifically, we detailed dose- and time-dependent dormancy of E. coli and its susceptibility to ofloxacin via arabinose-induced hipA toxin gene expression under the PBAD promoter. A new plot was developed to better describe the dynamic changes in culturability and persistence. The expression level of hipA was determined using qPCR and cellular activities were monitored using fluorescence imaging and flow cytometry. Results: High-level persister formation and strong tolerance to ofloxacin were observed after high-level hipA induction. The new plot reveals more information than the changes in persistence alone, e.g., reduced culturability of E. coli and thus deeper dormancy under high-level hipA induction. Consistently, controlled hipA induction led to decreased cellular activities at promoter PrrnBP1 and an increase in the non-culturable subpopulation. Conclusions: Overall, this study provides new insights into dormancy induced by toxin gene expression and a more comprehensive view of persistence and culturability. The findings may help develop better control agents against dormant bacterial cells. [ABSTRACT FROM AUTHOR]

Background: Application of electromembrane extraction coupled with capillary electrophoresis was studied for ofloxacin extraction from plasma samples. Methods: Ofloxacin migrated from acidic plasma samples through a thin layer of 1-octanol immobilized in the pores of a porous hollow fiber wall into a 10 µL acidic aqueous acceptor solution located inside the lumen of the fiber. Results: Under optimum conditions influencing electromigration (i.e., 20 min of the operation time, stirring speed of 750 rpm, donor phase pH at 4.0, acceptor pH at 3.0, and applied voltage of 30 V across the supported liquid membrane), ofloxacin was extracted from plasma samples with an enrichment factor of 100-fold corresponding to extraction percent of 24%. The calibration curve showed acceptable linearity in the range of 0.2-7.0 µg.mL-1 (R=0.9993). The limits of detection and quantification of 0.05 and 0.2 µg.mL-1 were obtained, respectively. The inter- and intra-day precision and accuracy were obtained below 8.65%. Conclusion: The validated method was successfully processed for the ofloxacin determination in the plasma samples of patients under ofloxacin therapy. There were no interfering peaks which indicates the great selectivity of the developed method.

This study proposed a novel electrochemical sensor for the sensitive measurement of the eye medication ofloxacin (OFX), which is based on a NiO@C-dot nanocomposite. The NiO@C-dot nanocomposite was synthesized using the sol-gel method, which was then applied to alter a glassy carbon electrode (GCE). With regard to OFX, the modified GCE shown outstanding electrochemical activity along with good sensitivity, selectivity, and stability. With OFX concentrations ranging from 5 µM to 975 µM, the NiO@C-dot/GCE showed a linear relationship with a sensitivity of 0.63994 µA/µM. The limit of detection (LOD) was 0.023 µM. The response to 50 µM OFX was measured, and the electrode was stored at 4°C after each test in order to evaluate the sensor's long-term stability and repeatability. After 20 days, the peak current response was still 97.89 % of its initial value. After 40 days of prolonged storage, 93.78 % of the electrode's original responsiveness was retained. The sensor showed a recovery rate of 97.37–99.70 % in all sample types when it was used to detect OFX in human urine, tap water, and food samples. These findings highlight the NiO@C-dot/GCE's outstanding selectivity, dependability, and longevity as solid platforms for OFX detection in complicated samples for a range of applications.

In order to establish an indirect competitive ELISA for the detection of ofloxacin (OFLX) residues in honey, in this study, OFLX was coupled to carrier proteins using the active ester method to obtain anti-OFLX complete antigen (OFLX-BSA) and detection antigen (OFLX-OVA). BALB/c mice were immunized with OFLX-BSA, after which anti-OFLX monoclonal antibodies were prepared by hybridoma and other techniques. An indirect competitive ELISA method was developed by optimizing the reaction conditions and the accuracy, precision and specificity of the method were determined. The results showed that OFLX was successfully coupled to the carrier protein, a hybridoma cell line (3D7) against OFLX was obtained. And the IC50 value of the monoclonal antibody was 1.17 ng/mL. The average recovery rate of OFLX spiked in honey by this method was 84.1%, and its intra-batch coefficients of variation were greater than inter-batch ones in all batches. The cross-reaction rate with marbofloxacin was 52.9%, and no cross-reaction with the other competing reactants. The indirect competitive ELISA method developed in this study is able to fulfill the requirements for determination of OFLX residues in honey.

Introduction. Fluoroquinolones remain the key second-line anti-tuberculosis drugs. The aim of the study was the molecular characterization of fluoroquinolone-resistant Mycobacterium tuberculosis strains from newly diagnosed tuberculosis patients in the Northwest of the Russian Federation. Materials and methods. The retrospective study collection included M. tuberculosis isolates isolated in 2015–2019 from previously untreated tuberculosis patients. Susceptibility to antituberculosis drugs (including the fluoroquinolone ofloxacin) was determined using the BACTEC MGIT960 or absolute concentration method. Mutations in the gyrA gene as a marker of resistance to fluoroquinolones, were detected by real-time PCR. Beijing genotype and its subtypes were detected by PCR and real-time PCR methods. Non-Beijing strains were spoligotyped. Results and discussion. Phenotypic resistance to ofloxacin was detected in 6.7% (40/599) of strains and in 17.4% (40/230) of MDR strains. 34 of 40 (85%) ofloxacin-resistant strains belonged to the Beijing genotype. 18 (45%) strains were assigned to the Russian epidemic subtype Beijing B0/W148 and 12 (30%) to Beijing Central Asian/Russian. The remaining 6 ofloxacin-resistant strains belonged to the Euro-American phylogenetic lineage. Mutations in the gyrA gene were found in 97.5% (39/40) of strains. The most common were mutations in codon 94 (69.2%, 27/39). The Asp94Gly substitution was identified in 57.5% (23/40) of ofloxacin-resistant strains and was dominant among Beijing (19/34) and non-Beijing (4/6) strains. The second most common substitution was Ala90Val (25%, 10/40). More than half of the ofloxacin-resistant strains, Beijing B0/W148 (10/18) and Central Asian/Russian (7/12), carried the Asp94Gly mutation. Conclusion. In the Northwest of Russia in 2016-2019, primary resistance of M. tuberculosis to fluoroquinolones was 6.7% in the total collection and 17.4% of MDR strains, and was mainly caused by the gyrA Asp94Gly and Ala90Val mutations. Beijing B0/W148 genotype was characterized by the largest proportion of fluoroquinolone-resistant strains.

Abstract 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.

Abstract A disposable screen-printed sensor has been crafted specifically for therapeutic drug monitoring purposes, particularly for detecting ofloxacin in biological fluids. To enhance selectivity toward ofloxacin, a supramolecular calix [6] arene serves as the ionophore of choice. The sensor incorporates a graphene nanocomposite as an ion-to-electron transducer layer, which not only boosts potential stability but also mitigates potential drift. The developed ofloxacin sensor underwent rigorous characterization following IUPAC guidelines. The linearity range spans from 1 × 10–6 to 1 × 10–2 M, with a measured slope of 59.0 mV/decade. Impressively, it boasts a percentage recovery of 100.18 ± 1.60 and a low detection limit (LOD) of 6 × 10–7 M. Stability assessments indicate reliable performance over an extended period of 8 weeks. The versatility of this sensor extends to various applications, including the determination of ofloxacin in pharmaceutical formulations, bulk powder, and biological fluids. Notably, it has demonstrated efficacy post-bioanalysis validation, adhering to Food and Drug Administration regulations. This advancement holds promise for personalized therapeutic drug monitoring in clinical pharmacy studies and quality control laboratories, thereby optimizing patient care at the point-of-care. Graphical abstract

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.

Ofloxacin (OFL) has antibacterial and anti‐inflammatory effects on respiratory tract infection, skin soft tissue infection and urogenital tract infection caused by sensitive bacteria. In this study, an electrochemical sensor on account of glassy carbon electrode (GCE) and anthraquinone (AQ)/Vulcan XC‐72 (C) composite was prosperity prepared for the determination of ofloxacin (OFL) drug. The morphology and structure of C/20%AQ composites were characterized by SEM. The electrochemical behavior of OFL on the C/20%AQ/GCE sensor was tested using differential pulse voltammetry (DPV) and cyclic voltammetry (CV). The consequences indicate that the linear response of the sensor to OFL at pH 6.5 in 0.2 M phosphate buffer solution (PBS) was in the scope of 0.1–550.0 μM (R2=0.998) with the limit of detection of 0.01 μM. The prepared C/20%AQ/GCE sensor exhibited good anti‐interference ability and repeatability against OFL. The sensor presents a sensitive, simple and low cost OFL detection method, and has been successfully applied to real samples. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

A disposable screen-printed sensor has been crafted specifically for therapeutic drug monitoring purposes, particularly for detecting ofloxacin in biological fluids. To enhance selectivity toward ofloxacin, a supramolecular calix [6] arene serves as the ionophore of choice. The sensor incorporates a graphene nanocomposite as an ion-to-electron transducer layer, which not only boosts potential stability but also mitigates potential drift. The developed ofloxacin sensor underwent rigorous characterization following IUPAC guidelines. The linearity range spans from 1 × 10–6 to 1 × 10–2 M, with a measured slope of 59.0 mV/decade. Impressively, it boasts a percentage recovery of 100.18 ± 1.60 and a low detection limit (LOD) of 6 × 10–7 M. Stability assessments indicate reliable performance over an extended period of 8 weeks. The versatility of this sensor extends to various applications, including the determination of ofloxacin in pharmaceutical formulations, bulk powder, and biological fluids. Notably, it has demonstrated efficacy post-bioanalysis validation, adhering to Food and Drug Administration regulations. This advancement holds promise for personalized therapeutic drug monitoring in clinical pharmacy studies and quality control laboratories, thereby optimizing patient care at the point-of-care. [ABSTRACT FROM AUTHOR]

SiO2 @ g-C3 N4 Core-shell nanospheres and Ag/AgCl/SiO2 @ g-C3 N4 composites were synthesized by hard template method, their structure and optical properties were characterized. The performance and mechanism of visible light photocatalytic degradation of ofloxacin (OFX) were investigated. The results showed g-C3 N4 is coated on the surface of SiO2 nanospheres, most of them are spheres with a diameter of 400 nm. The addition of Ag/AgCl constructs a heterojunction and significantly improves the separation efficiency of photogenerated carriers. Compared with pure g-C3 N4, the photocatalytic degradation of ofloxacin by Ag/AgCl/SiO2@ g-C3 N4 composites was significantly improved. When the initial concentration of OFX is 10 mg/L, the catalyst dosage is 0.2 g/L, and the degradation rate of OFX can reach 72.59% after 40 min of visible light irradiation at 100 mW/cm². Free radical quenching experiments showed that the main active substance in the photocatalytic degradation of pollutants by Ag/AgCl/SiO2@ g-C3 N4 composite was photogenerated holes. [ABSTRACT FROM AUTHOR]

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). [ABSTRACT FROM AUTHOR]

The oxidative degradation of an antibiotic, Ofloxacin (OFX), has been investigated using the electro-Fenton (EF) process with a constant current between 100 and 500 mA and a carbon-felt cathode. The kinetics of oxidative degradation and the efficiency of mineralization were examined about the applied current and catalyst (Fe2+) concentration. The absolute rate constant for the oxidation of OFX by hydroxyl radical was determined using the competition kinetic approach as 3.04 ± 0.19 × 109 M–1s–1. For efficient degradation of OFX at the relevant operating conditions, the ideal current value is 400 mA at a concentration of the catalyst (Fe2+) at 0.10 mM. After 6 h of electrolysis, in the present study, it is demonstrated that several cathodes, including carbon felt (CF), carbon-graphite (CG) and stainless steel (SS), had an impact on the electrochemical oxidation of the organic contaminant, OFX. A high level of mineralization (>97%) was attained. The development of F−, and ions was also monitored and their evolution during their release into the medium was discussed. Several intermediate products were identified using LC-MS/MS (liquid chromatography-mass spectrometry) and HPLC (High-performance liquid chromatography) analyses. Based on the identity of these products, a feasible route for the mineralization process is proposed. Finally, biodegradability was studied and the results indicated the following ratio of biological oxygen demand within 5 days to chemical oxygen demand BOD5/COD through OFX mineralization by EF treatment for the possibility of evaluating the combination of electro-Fenton and biological treatment. [ABSTRACT FROM AUTHOR]

Objective: This study aimed to evaluate the determination uncertainty of four quinolones residues in honey by liquid chromatography-tandem mass spectrometry （LC-MS/MS）. Methods: Based on GB 31657.2—2021, a mathematical model for sources of uncertainty evaluation was established. The uncertainty of each variable which affect the result were calculated and the weight of each uncertainty component was assessed. Results: The uncertainties in the determination of enrofloxacin, sarafloxacin, ofloxacin and ciprofloxacin in honey were （4.97±0.81）, （10.13±1.58）, （7.67±1.23）, （14.97±2.25） μg/kg （P=95%，k=2） respectively. Conclusion: The main influencing factors of the determination uncertainty were preparation and dilution process of standard solution and fitting of standard curve, which should be controlled in practical work.

To date, the systematic summarization and comprehensive review of analysis, distribution, migration, and degradation of chiral antibiotics in the vadose zone are limited. This review indicates that the physicochemical characteristics of chiral antibiotics are quite different, for instance, the solubility and octanol-water partition coefficient (lg Kow) of S-gemifloxacin are 301 times and 9.8 times larger than the values of R-gemifloxacin, which will affect their migration and degradation in the environment. High performance liquid chromatography with chiral column and chiral ligand-exchange chromatography are the common methods on the chiral antibiotics analysis. The concentrations of chiral antibiotics in soils, waters, and agricultural products in China and abroad are reported; flumequine, lomefloxacin and ofloxacin are the most common antibiotics. The adsorption rate and partition coefficient (Kd) of chiral antibiotics during their adsorption on minerals and microplastics are different, especially in the presence of natural organic matter (NOM); however, there is no relationship among the various types of chiral antibiotics. Chiral antibiotics can be complexed with the common cations, and their stability constants are quite different in the groundwater, for instance, the stability constant of Mg2+-levofloxacin is 22.9 times larger than that of Mg2+-ofloxacin. During the biodegradation process, the degradability and rate of chiral antibiotics are also different. Additionally, the chiral antibiotics can be transformed reciprocally. In this review, the distribution, migration, and degradation of chiral antibiotics in the vadose zone are investigated, which is beneficial to the study on the chiral antibiotics in the groundwater. As to the environmental fate of chiral antibiotics in the vadose zone, the following researches are recommended: (1) the resolution, analysis, toxicology, and standard establishment of chiral antibiotics; (2) the investigation, migration, and degradation of multiple chiral antibiotics; (3) the environmental processes of chiral antibiotics in the multi-interface.

Within epithelial cells, Pseudomonas aeruginosa depends on its type III secretion system (T3SS) to escape vacuoles and replicate rapidly in the cytosol. Previously, it was assumed that intracellular subpopulations remaining T3SS-negative (and therefore in vacuoles) were destined for degradation in lysosomes, supported by data showing vacuole acidification. Here, we report in both corneal and bronchial human epithelial cells that vacuole-associated bacteria can persist, sometimes in the same cells as cytosolic bacteria. Using a combination of phase-contrast, confocal, and correlative light-electron microscopy (CLEM), we also found they can demonstrate biofilm-associated markers: cdrA and cyclic-di-GMP (c-di-GMP). Vacuolar-associated bacteria, but not their cytosolic counterparts, tolerated the cell-permeable antibiotic ofloxacin. Surprisingly, use of mutants showed that both persistence in vacuoles and ofloxacin tolerance were independent of the biofilm-associated protein CdrA or exopolysaccharides (Psl, Pel, alginate). A T3SS mutant (ΔexsA) unable to escape vacuoles phenocopied vacuole-associated subpopulations in wild-type PAO1-infected cells, with results revealing that epithelial cell death depended upon bacterial viability. Intravital confocal imaging of infected mouse corneas confirmed that P. aeruginosa formed similar intracellular subpopulations within epithelial cells in vivo. Together, these results show that P. aeruginosa differs from other pathogens by diversifying intracellularly into vacuolar and cytosolic subpopulations that both contribute to pathogenesis. Their different gene expression and behavior (e.g., rapid replication versus slow replication/persistence) suggest cooperation favoring both short- and long-term interests and another potential pathway to treatment failure. How this intracellular diversification relates to previously described "acute versus chronic" virulence gene-expression phenotypes of P. aeruginosa remains to be determined. IMPORTANCE Pseudomonas aeruginosa can cause sight- and life-threatening opportunistic infections, and its evolving antibiotic resistance is a growing concern. Most P. aeruginosa strains can invade host cells, presenting a challenge to therapies that do not penetrate host cell membranes. Previously, we showed that the P. aeruginosa type III secretion system (T3SS) plays a pivotal role in survival within epithelial cells, allowing escape from vacuoles, rapid replication in the cytoplasm, and suppression of host cell death. Here, we report the discovery of a novel T3SS-negative subpopulation of intracellular P. aeruginosa within epithelial cells that persist in vacuoles rather than the cytoplasm and that tolerate a cell-permeable antibiotic (ofloxacin) that is able to kill cytosolic bacteria. Classical biofilm-associated markers, although demonstrated by this subpopulation, are not required for vacuolar persistence or antibiotic tolerance. These findings advance our understanding of how P. aeruginosa hijacks host cells, showing that it diversifies into multiple populations with T3SS-negative members enabling persistence while rapid replication is accomplished by more vulnerable T3SS-positive siblings. Intracellular P. aeruginosa persisting and tolerating antibiotics independently of the T3SS or biofilm-associated factors could present additional challenges to development of more effective therapeutics.