Synthesis, Characterization, and Pharmacodynamics Study of Enrofloxacin Mesylate

Simultaneous detection of enrofloxacin and florfenicol in animal-derived foods based on fluorescence quenching BELISA and a nanozyme catalytic strategy

Enrofloxacin (ENRO) and florfenicol (FF) are animal-specific drugs, but they present great harm to human health. Therefore, it is essential to rapidly and accurately detect ENRO and FF in animal-derived foods simultaneously. Herein, dual-template molecular imprinted polymers (MIPs) with specific recognition of ENRO and FF were prepared, meanwhile, the molar ratios of templates to monomer and cross-linker were optimized and then applied as a bionic antibody to experiment. Based on the principle that the fluorescence of QDs could be efficiently quenched by the enzymatic fabrication of Prussian blue nanoparticles (PBNPs), a novel and sensitive fluorescence quenching biomimetic enzyme-linked immunosorbent assay (BELISA) was established for simultaneous detection of ENRO and FF by the conversion of the absorption signal into fluorescent signals. Under optimal conditions, the detection limit (IC15) was 4.64 ng L-1 for ENRO and 1.33 ng L-1 for FF. Besides, matrix interference of chicken, eggs, milk and shrimp samples, was investigated in our study, and the result indicates that all of the sample matrices had a profound impact on the fluorescence of QDs, especially for milk samples (with Im of 94.10 %). After performing the matrix-elimination experiments, chicken, eggs, milk and shrimp samples spiked with ENRO and FF were extracted and detected by this proposed method, with recoveries ranging from 82.70 to 113.48 %. The results correlated well with those obtained using HPLC. In conclusion, the developed method could be an alternative and sensitive method for the simultaneous detection of ENRO and FF in animal-derived foods.

Enhancing the solubility and antibacterial activity of novel molecular salts of enrofloxacin drug with isomeric pyridinedicarboxylic acids

Enrofloxacin (EFX) is a third-generation synthetic fluoroquinolone with a broad spectrum of antibacterial activity but suffers from low water solubility, affecting its bioavailability. This study attempts to enhance the physicochemical and biological properties of enrofloxacin by converting it into multicomponent forms using crystal engineering concepts. Cocrystallization of enrofloxacin with isomeric pyridine-2,n-dicarboxylic acids (n = 3,4,5,6) resulted in four new crystalline salts (1:1): EFX·Py2,3DCA, EFX·Py2,4DCA, EFX·Py2,5DCA·H2O and EFX·Py2,6DCA·H2O; two of these are monohydrates. The protonation of the nitrogen atom of the piperazine moiety and the presence of crystallization water molecules were confirmed by single-crystal X-ray diffraction and Fourier transform infrared spectroscopy. Thermogravimetric analysis provided information on the thermal behaviour of multicomponent forms. The biological studies showed that the obtained salts are characterized by high antibacterial activity against Gram-positive and Gram-negative bacteria, and their haemolytic activity is low. The new salts demonstrate significantly greater solubility in water compared to the parent drug, along with enhanced antibacterial activity; hence, pyridinedicarboxylic acids appear to be efficient cocrystallizing agents for improving the efficacy of pharmaceutical ingredients.

Impact of graded doses of enrofloxacin on the safety and biological responses of Nile tilapia Oreochromis niloticus

The cultivation of tilapias, the third most farmed fish group globally, has been rapidly growing, especially in Southeast Asia. This surge in tilapia farming intensification has led to increased use of antibiotics to control bacterial diseases. This study investigated the safety implications of administering graded doses of enrofloxacin (ENF) at 0 (control), 10, 30, 50 and 100 mg/kg biomass/day orally to Oreochromis niloticus. The 43-day study comprised 7 days of pre-dosing, 15 days of ENF-dosing, and a 21-day recovery period with a periodical assessment of the biological responses of fish. The results revealed that the overdosed groups experienced up to 21% reduction in feed consumption, 11% mortalities, and adverse impacts on hematology, including a decrease in erythrocytes, and monocytes and an increase in leukocytes, thrombocytes, lymphocytes, and neutrophils. Haematological indices like mean corpuscular volume and mean corpuscular hemoglobin decreased, while mean corpuscular hemoglobin concentration increased. The plasma biochemical parameters including glucose and liver and kidney enzymes unveiled a significant dose- and time-dependent increase, while calcium and chloride levels decreased. Erythrocytes displayed several erythrocyte cellular and nuclear abnormalities. The frequency of micronucleus increased with dose and time, suggesting potential genotoxicity of ENF. Additionally, a dose-dependent increase in residues in the tissues with the highest accumulation in muscle was documented. Nevertheless, the recovery of the measured parameters upon dose termination indicated that the ENF-induced alterations are reversible. The study affirmed the safety of ENF at the recommended dose (10 mg) in O. niloticus and their adoptive responses to higher doses.

Detection of enrofloxacin residues in dairy products based on their fluorescence quenching effect on AgInS2 QDs

Water-soluble AgInS₂ (AIS) quantum dots (QDs) were successfully prepared through the one-pot water phase method with thioglycolic acid (TGA) as the stabilizing agent. Because enrofloxacin (ENR) effectively quenches the fluorescence of AIS QDs, a highly-sensitive fluorescence detection method is proposed to detect ENR residues in milk. Under optimal detection conditions, there was a good linear relationship between the relative fluorescence quenching amount (ΔF/F₀) of AgInS₂ with ENR and ENR concentration (C). The detection range was 0.3125-20.00 μg/mL, r = 0.9964, and the detection limit (LOD) was 0.024 μg/mL (n = 11). The average recovery of ENR in milk ranged from 95.43 to 114.28%. The method established in this study has advantages including a high sensitivity, a low detection limit, simple operation and a low cost. The fluorescence quenching mechanism of AIS QDs with ENR was discussed and the dynamic quenching mechanism of light-induced electron transfer was proposed.

Targeting therapy effects of composite hyaluronic acid/chitosan nanosystems containing inclusion complexes

In order to solve the difficulties in the treatment of Staphylococcus aureus infections, a novel enrofloxacin-cyclodextrin (β-CD) inclusion complexes (IC) containing hyaluronic acid/chitosan (HA/CS) self-assemble composite nanosystems covered by poloxamer 188 was designed in our previous study. In this study, the sustained release peforemance, targeting delivery, and therapy effects of the enrofloxacin-composite nanosystems were evaluated in vivo. The enrofloxacin-composite nanosystems had uniform size and smooth surface with drug loading capacity (LC) of 9.92 ± 0.3%. Thermogravimetric analysis (TGA) showed that the material used for the preparation of the enrofloxacin-composite nanosystems did not affect the thermal stability of enrofloxacin. Compared with enrofloxacin injection and enrofloxacin polymeric nanoparticles, the enrofloxacin-composite nanosystems had excellent sustained-release performance in vivo. The enrofloxacin-composite nanosystems have specific targeting to the infection site of Staphylococcus aureus. The excellent sustained release and targeting delivery properties ensure that the anti-infective treatment effect of the enrofloxacin-composite nanosystems in vivo was higher than that of enrofloxacin injection and enrofloxacin polymeric nanoparticles. It can more effectively promote the wound healing. These results suggest that our previous designed enrofloxacin-composite nanosystems will be a promising formulation for effective targeting therapy of Staphylococcus aureus infections.

Interaction of Antibiotics and Humic Substances: Environmental Consequences and Remediation Prospects

The occurrence and distribution of antibiotics in the environment has received increasing attention due to their potential adverse effects on human health and ecosystems. Humic substances (HS) influence the mobility, reactivity, and bioavailability of antibiotics in the environment significantly due to their interaction. As a result, HS can affect the dissemination of antibiotic-resistance genes, which is one of the main problems arising from contamination with antibiotics. The review provides quantitative data on the binding of HS with fluoroquinolones, macrolides, sulfonamides, and tetracyclines and reports the proposed mechanisms of their interaction. The main issues of the quantification of antibiotic-HS interaction are discussed, which are a development of standard approaches and the accumulation of a dataset using a standard methodology. This would allow the implementation of a meta-analysis of data to reveal the patterns of the binding of antibiotics to HS. Examples of successful development of humic-based sorbents for fluoroquinolone and tetracycline removal from environmental water systems or polluted wastewaters were given. Data on the various effects of HS on the dissemination of antibiotic-resistance genes (ARGs) were summarized. The detailed characterization of HS properties as a key point of assessing the environmental consequences of the formation of antibiotic-HS complexes, such as the dissemination of antibiotic resistance, was proposed.

Fabrication of graphene oxide/inulin impregnated with ZnO nanoparticles for efficient removal of enrofloxacin from water: Taguchi-optimized experimental analysis

A novel nano-adsorbent zinc oxide impregnated graphene oxide/inulin (ZGI) was prepared for the investigation of the removal efficiency of enrofloxacin. Characterization of the nano-adsorbent was accomplished through Fourier transform Infrared (FTIR) spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM) coupled with EDS, transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy. The average crystallite size of nanomaterial (ZGI) calculated from XRD data was 14.82 nm. The adsorption of enrofloxacin onto ZGI was performed in batch mode. The variables of adsorption process such as adsorbent dose, pH, contact time and initial concentration of enrofloxacin were optimized by Taguchi method to achieve the maximum removal efficiency. The optimum values of variables were: adsorbent dose = 25 mg, pH = 7, contact time = 60 min and initial concentration = 50 mg/L. The maximum adsorption capacity and removal efficiency of the material for enrofloxacin were 317.83 mg/g and 98.60%, respectively at 303 K. Redlich-Peterson isotherm model was the best fitted among the various isotherm models based on highest R² values (0.9978-0.9981) and lowest χ² (3.43 ×10^-4-2.00×10^-3). Kinetic data followed pseudo-second order model (R² ≥ 0.9974) more accurately as compared to pseudo-first order model (R²≤0.9772). The adsorption mechanism was illustrated on the basis of XPS and Raman studies. Reusability investigation showed that the nano-adsorbent ZGI could be used up to 5 adsorption-desorption cycles with greater than 90% removal efficiency.

pH-driven entrapment of enrofloxacin in casein-based nanoparticles for the enhancement of oral bioavailability

Enrofloxacin (ENR), a broad-spectrum antibacterial drug, has extremely poor water solubility contributing to low bioavailability, which prevents drug formulation design and limits its wide application in livestock farming and aquaculture. Compared to conventional formulations of ENR, casein (Cas)-based drug delivery system has been reported to have significant advantages in the improvement of solubility and bioavailability of drugs. In this paper, we report the preparation process of ENR-loaded Cas nanoparticles (ENR-Cas) using magnetic agitation without any organic agent and the optimization of the formulation. Transmission electron microscopy (TEM), dynamic light scattering (DLS), differential scanning calorimetry (DSC), powder X-ray diffraction (PXRD), and Fourier transform infrared spectroscopy (FTIR) were all adopted to characterize the ENR-Cas. Results showed that the obtained ENR-Cas were approximately spherical with a particle size of 171.6 ± 13.8 nm with a polydispersity index of 0.322 ± 0.053. In vitro release behavior of ENR-Cas showed a sustained release profile. Additionally, in vivo study in rats displayed that the mean plasma concentration of ENR after oral administration of ENR-Cas was significantly higher than that treated with ENR suspension. The mean residence time (MRT0-24) of ENR was enhanced by Cas nanoparticles from 9.287 ± 0.524 to 11.372 ± 1.139 hr in comparison with ENR suspension. Accordingly, the area under the curve (AUC0-24) of ENR-Cas was 80.521 ± 6.624 μg·hr/ml, 3.8-fold higher than that of ENR suspension (20.850 ± 1.715 μg·hr/ml). Therefore, it can be concluded that ENR-Cas enhanced the absorption, prolonged the retention time, and improved oral bioavailability of ENR. Taken the good oral safety of Cas into consideration, ENR-Cas should be a more promising oral preparation of ENR for clinical application.