Roxithromycin

To facilitate the application of partial nitritation (PN) - anaerobic ammonium oxidation process in nitrogen removal from livestock wastewater, the inhibition of roxithromycin (ROX) and Cu(II) on the PN sludge was examined using a respirometric method. The results showed that the IC50 of ROX and Cu(II) on PN sludge were 346 and 74.3mgL-1, respectively. The relative specific respiration rate (SRR) of ammonia-oxidizing bacteria (AOB) decreased from 87.4% to 17.7% with the ROX concentration increased from 0 to 500mgL-1. When the concentration of Cu(II) increased from 0 to 160mgL-1, the SRRs of AOB and nitrite-oxidizing bacteria decreased by 85.5% and 11.2%, respectively. According to the isobole plots analysis, combined suppression by ROX and Cu(II) was synergistic. Fourier transform infrared spectroscopy analyses showed that ROX exposure altered the positions of CO bonds, and the intensity of the absorption peak at 2100cm-1 changed under Cu(II) exposure.

An outbreak of infections with a high mortality rate caused by multidrug resistant (MDR) bacteria is one of the biggest health challenges globally. A class IV drug, roxithromycin (ROX), has poor solubility. In this study, ROX was first encapsulated in the cavity of each of the β-cyclodextrin (βCD) and hydroxypropyl-β-cyclodextrin (HPβCD). Then, each of the resulting βCD-ROX inclusion complex and HPβCD-ROX inclusion complex were separately loaded into poly-(lactic-co-glycolic acid) (PLGA) to synthesize βCD-ROX/PLGA and HPβCD-ROX/PLGA nanoparticles (NPs). Blank and ROX loaded PLGA (ROX-PLGA) NPs were also prepared. The loading efficiency of ROX is comparatively high for HPβCD-ROX/PLGA NPs in comparison to the βCD-ROX/PLGA NPs and ROX-PLGA NPs. All designed formulations showed significant (P<0.0001) antibacterial activity against the selected MDR bacterial strains. In a nutshell, this study demonstrated a great therapeutic potential of the above-mentioned delivery systems for treatment of MDR bacteria.