Amoxicillin-Loaded Polymeric Nanoparticles of Less than 100 nm: Design, Preparation and Antimicrobial Activity Against Methicillin-Resistant Staphylococcus aureus

摘要

Amoxicillin is commonly used to treat a wide range of infections, but its use is limited by a relatively short biological half-life. This study developed a controlled-release amoxicillin nanoformulation and evaluated its antibacterial activity. The nanoparticles were synthesized by ionic gelation method assisted by sonication and characterized by Fourier transformed infrared, scanning electron microscopy and dynamic light scattering. The antibacterial effect was studied using micro-dilution method to determine the minimum inhibitory concentration of nanoparticles. Inhibition zone diameters of nanoformulation were also compared to those of the free amoxicillin. Sonication reduced the average size of nanoparticles by 70%. The encapsulation efficiency was 95 +/- 2%. In vitro release studies showed the initial burst release in the first 10h and continuous slow release up to the end. The antimicrobial results indicated that the amoxicillin-loaded chitosan nanoparticles were more effective than free amoxicillin against methicillin-susceptible- and methicillin-resistant forms of Staphylococcus aureus. The results highlight that the chitosan and sodium tripolyphosphate concentration and the sonication has a significant influence on nanoparticle size. The optimized chitosan nanoparticles with proper size and controlled release of -lactam antibiotics may be a good candidate for treating antibiotic-resistant Staphylococcus aureus infections.