Efficacy and pharmacodynamics of gemifloxacin versus levofloxacin in guinea pig pneumococcal pneumonia induced by strains with decreased ciprofloxacin susceptibility

Construction of novel magnetic nanoparticles for enrichment of benzo(α)pyrene from edible oils followed by HPLC determination

A novel method for benzo(α)pyrene (Bαp) enrichment from an oil matrix was developed by using magnetic nanoparticles (Fe₃O₄@dopamine/graphene oxide, Fe₃O₄@DA/GO) as extraction absorbents, and the chemical properties of the synthesized nanoparticles were characterized. Various parameters were investigated to optimize the extraction of Bαp from oils. Under optimal conditions (pH, 4; extraction time, 0.5 min; elution solvent, 1 mL; absorbent weight, 20 mg; elution time, 0.5 min), these nanoparticles showed excellent abilities to enrich Bαp from the saponified oil solution and were easily separated by a magnet. High-performance liquid chromatography plus fluorescence detection (HPLC-FLD) was then applied to determine the Bαp content with excellent linearity (R² = 0.999). The detection limit was 0.13 µg/kg, while the limit of quantification was 0.42 µg/kg. The spiked recoveries of Bαp in oils ranged from 73.5% to 121%. Compared with previous reports, the proposed method displayed many advantages, including a high efficiency of oil matrix removal, short extraction time, and convenient extraction procedure.

In vivo activity of gemifloxacin, moxifloxacin and levofloxacin against pneumococci with gyrA and parC point mutations in a sepsis mouse model measured with the all or nothing mortality end-point

A dose-decreasing immunocompetent sepsis mouse model was used to evaluate the in vivo effect of levofloxacin, moxifloxacin and gemifloxacin, using a ciprofloxacin/levofloxacin susceptible serotype 6B strain (ciprofloxacin MIC: 1 mg/l) and two resistant serotype 14 and 19F strains with gyrA and parC point mutations (ciprofloxacin MICs of 32 and 64 mg/l, respectively). Significant higher in vivo activity was found for moxifloxacin and gemifloxacin than for levofloxacin against strains 1 and 2, and for gemifloxacin versus moxifloxacin or levofloxacin against strain 3. Gemifloxacin treatment resulted in 100% survival against strains 1 and 2(AUC0-24 h/MIC of 30 and 62) but against strain 3, survival was 60-80% (AUC0-24 h/MIC of 93). Similar AUC0-24 h/MIC values produced different therapeutic results suggesting that in vitro parameters other than the MIC could influence efficacy predictions based on in vitro susceptibility tests (MICs) or pharmacodynamic parameters (AUC0-24 h/MIC).