The Effect of Nanoformulation of Amoxicillin on its Antibacterial Activity Against Common Bacterial Strains Involved in Hospital-Acquired Infections

Nanotechnology offers a great chance to treat drug-resistant microbial infections. The purpose of this study was to synthesize amoxicillin-encapsulated polymeric nanoparticles and compare the antibacterial activity of this nanoformulation with pure amoxicillin.
Amoxicillin-encapsulated polymeric nanoparticles were prepared using chitosan as a polymer and alginate as cross linking agent. The obtained nanoparticles were characterized by Fourier transform infrared, dynamic light scattering and scanning electron microscopy. The antibacterial effects of the nanoparticles were evaluated using broth microdilution and well diffusion methods against some common bacterial strains involved in hospital-acquired infections.
The drug-encapsulated nanoparticles were found to be spherical in shape with average size of 96 nm. These nanoparticles had a significant antibacterial effect on all tested bacteria, except for Pseudomonas aeruginosa. They also displayed stronger antibacterial activity than the nanocarrier alone or free antibiotic. The highest mean zones of growth inhibition (23.7 mm) for methicillin-sensitive Staphylococcus aureus and the smallest zone (12.5 mm) for the resistant species of this bacterium were determined. MIC of the nanoformulation against these two strains was respectively determined at 1.5 and 48 µg/ml and for Escherichia coli and Pseudomonas aeruginosa at 6.6 and 256 µg/ml.
The results suggest that amoxicillin encapsulation in polymer nanoparticles has the potential to increase its antibacterial activity against bacteria causing nosocomial infections.