Metronidazole-Loaded Chitosan Nanoparticles with Antimicrobial Activity Against Clostridium perfringens

Background/Objectives: Even with improvements in surgical techniques and the application of appropriate antibiotic prophylaxis, wound infections are still major public health problems in low- and middle-income countries. This study proposes the design of new particulate polymeric matrices based on chitosan (CS) for the controlled release of Metronidazole (MTZ), in order for it to be used for the treatment of Clostridium perfringens infections. Methods: The nanoparticles were prepared via inverse emulsion using tannic acid (TA) and sodium tripolyphosphate (TPP) as cross-linking agents. The ratio of CS to TPP, the concentration of CS solution, and the ratio of CS to TA were varied to optimize the synthesis procedure. Nanoparticles have been characterized based on several points of view in order to correctly correlate their properties with synthesis parameters. Results: The FTIR spectra of the analyzed nanoparticles confirmed both the formation of hydrogen bonds between CS and TA and the ionic cross-linking of CS with TPP. The average diameters of the nanoparticles ranged from 70 to 170 nm, whereas the zeta potential values were around 8 mV. Their swelling degree in a weak basic environment, as well as the drug loading/release capacity was influenced, as expected, by the synthesis parameters. The obtained nanoparticles were tested in vitro to evaluate their behavior in the blood environment, the cytotoxic effect, and the antimicrobial activity of nanoparticles loaded with MTZ against Clostridium perfringens cultures. Conclusions: The in vitro obtained results demonstrate that these non-hemolytic and non-cytotoxic particles can be efficient drug delivery systems for the treatment of Clostridium perfringens in wound infections.