Development and Validation of Stability-Indicating HPLC Methods for the Estimation of Lomefloxacin and Balofloxacin Oxidation Process under ACVA, H2O2, or KMnO4 Treatment. Kinetic Evaluation and Identification of Degradation Products by Mass Spectrometry

Phosphorus-modified copper ferrite (P-CuFe2O4) nanoparticles for photocatalytic ozonation of lomefloxacin

Phosphorus-modified copper ferrite (P-CuFe2O4) nanoparticles were prepared by a simple sol-gel auto-combustion process and used for the photocatalytic ozonation of lomefloxacin (LOM). The morphology, crystallinity, and structure of the synthesized CuFe2O4 and P-CuFe2O4 nanoparticles were investigated using various techniques. The high-performance liquid chromatography (HPLC) analysis revealed that the degradation of LOM achieved a 99% reduction after a duration of 90 min in the photocatalytic ozonation system. In accordance with the charge-to-mass ratio, four intermediates were proposed with the help of their fragments obtained in LC-MS/MS. The degradation kinetics of lomefloxacin followed a pseudo-first order reaction, and the degradation mechanism was proposed based on the results. P0.035Cu0.965Fe2O4 showed the highest total organic carbon (TOC) removal with 20.15% in 90 min, highest specific surface area and the highest fluoride and ammonium production using the ion chromatography (IC). The experimental results obtained from the electron paramagnetic resonance (EPR) analysis indicated that the modified P-CuFe2O4 samples exhibited significantly elevated levels of superoxide (.O2-) production compared to the CuFe2O4 samples. The findings of this study demonstrate that the introduction of phosphorus modification into the copper ferrite photocatalyst led to an augmentation of both the specific surface area and the total pore volume. Furthermore, the incorporation of phosphorus served to promote the efficient separation of electron-hole pairs by effectively trapping electrons in the conduction band, hence enhancing the degradation efficiency.

Feasible spectrofluorimetric approach for the ultrasensitive determination of lomefloxacin based on synergistic effects of micellization and metal complexation

The purpose of the present work was to establish a fast and convenient strategy for lomefloxacin analysis using a fluorimetric approach. The methodology was based on the complex formation of the drug with aluminum ion to give a product having high fluorescence. Adding sodium dodecyl sulfate led to further boosting the intensity of fluorescence which was recorded at 429 nm after excitation at 332 nm. The relationship of emission intensity with lomefloxacin concentration was linear at 10-130 ng mL^-1 with a correlation coefficient of 0.9996. The quantitation limit was 11.4 ng mL^-1 and detection limit was 3.8 ng mL^-1. The reaction conditions were carefully studied which included the pH, buffer type, its concentration, the type and concentration of surfactant and the diluting solvent. The method was utilized to quantify the aforementioned drug in tablet formulations and in real human plasma with high accuracy and reliability.

Synthesis and application of novel N, Si-carbon dots for the ratiometric fluorescent monitoring of the antibiotic balofloxacin in tablets and serum

A ratiometric fluorescent probe with blue-emission fluorescence based on N, Si-doped carbon dots (N, Si-CDs) for the detection of balofloxacin (BLFX) was synthesized by simple one-pot hydrothermal carbonization using methotrexate and 3-aminopropyltriethoxysilane (APTES) as carbon materials. The obtained N, Si-CDs showed dual-emission band fluorescence characterization at 374 nm and 466 nm. Furthermore, the synthesized N, Si-CD probe exhibited evidence of ratiometric fluorescence emission characteristics (F₄₆₆/F₃₇₄) toward BLFX along with a decrease in fluorescence intensity at 374 nm and an increase in fluorescence intensity at 466 nm. Based on this probe, a highly sensitive and fast detection method for the analysis of BLFX has been established with a linear range of 1–60 μM and a low detection limit of 0.1874 μM, as well as a rapid response time of 5.0 s. The developed assay has also been successfully applied for the detection of BLFX in tablets and rat serum.

A ratiometric fluorescent probe with blue-emission fluorescence based on N, Si-doped carbon dots (N, Si-CDs) for the detection of balofloxacin (BLFX) was synthesized by a simple method.

Study of Oxidation of Ciprofloxacin and Pefloxacin by ACVA: Identification of Degradation Products by Mass Spectrometry and Bioautographic Evaluation of Antibacterial Activity

The new RP-HPLC-DAD method for the determination of ciprofloxacin and pefloxacin, next to their degradation products after the oxidation reaction with 4,4′-azobis(4-cyanopentanoic acid) (ACVA) was developed. The method was validated according to the guidelines of the International Council for Harmonization of Technical Requirements for Pharmaceuticals for Human Use (ICH) and meets the acceptance criteria. The experimental data indicate that the course of the oxidation process depends on the type of fluoroquinolone (FQ), the incubation time and temperature. The performed kinetic evaluation allowed us to state that the oxidation of FQs proceeds according to the second-order kinetics. The degradation products of the FQs were identified using the UHPLC-MS/MS method and their structures were proposed. The results obtained by the TLC-direct bioautography technique allowed us to state that the main ciprofloxacin and pefloxacin oxidation products probably retained antibacterial activity against Escherichia coli.