Anti Pneumococcal Activity of Azithromycin-Eudragit RS100 Nano-Formulations

Bacterial pneumonia is a common lung infection caused by different types of bacteria. Azithromycin (AZI), an azalide antibiotic, is widely used to manage pneumococcal infections. Studies have shown that antibiotics in nanocarriers may lead to increased antibacterial activity and reduced toxicity. The aim of this work was to valuate in vitro antibacterial performance azithromycin-Eudragit RS100 nano-formulations against Streptococcus pneumoniae and Staphylococcus aureus. AZI-Eudragit RS100 nanoparticles were prepared via electrospinning technique and the in vitro antibacterial performance against S. pneumoniae and S. aureus were assessed using agar dilution method. Nanofibers in the sizes about 100-300 nm in diameter and micro scale in length and nanobeads in the range of 100-500 nm were achieved. The Minimum Inhibitory Concentrations (MIC) showed an enhancement in the antimicrobial effect of AZI-Eudragit RS100 nanofibers (40 µg/ml) compare to untreated AZI solution (>160 µg/ml) against S. pneumonia. The MIC value for AZI-Eudragit RS100 nanofibers against S. aureus was >128 µg/ml, same as that of the untreated AZI solution. The enhanced efficiency of AZI in nanofibers could be related to the more adsorption opportunity of nanofibers to S. pneumonia capsulated cell wall which provides an antibiotic depot on the bacterial surface compared to S. aureus. AZI-Eudragit RS100 nanofibers with enhanced antimicrobial effect against S. pneumonia can be considered as a candidate for in vivo evaluations in antibiotic therapy of Pneumococcal infections.