Chitosan/starch nanocomposites loaded with ampicillin were prepared using the spray-drying method by mixing various ratios of chitosan and starch. The morphology of chitosan/starch nanoparticles was studied using a scanning electron microscope (SEM), and the zeta potential value and size distribution were determined by a Nanoparticle Analyzer. The results show that the chitosan/starch nanocomposites have a spherical shape, smooth surface, and stable structure. Nanoparticle size distribution ranged from 100 to 600 nm, and the average particle size ranged from 300 to 400 nm, depending on the ratio between chitosan and starch. The higher the ratio of starch in the copolymer, the smaller the particle size. Zeta potential values of the nanocomposite were very high, ranging from +54.4 mV to +80.3 mV, and decreased from 63.2 down to +37.3 when loading with ampicillin. The chitosan/starch nanocomposites were also characterized by FT-IR to determine the content of polymers and ampicillin in the nanocomposites. The release kinetics of ampicillin from the nanocomposites were determined in vitro using an HPLC profile for 24 h. The loading efficiency (LE) of ampicillin into chitosan/starch nanoparticles ranged from 75.3 to 77.3%. Ampicillin-loaded chitosan/starch nanocomposites were investigated for their antibacterial activity against antibiotic-resistant Escherichia coli in vitro. The results demonstrate that the antibacterial effectiveness of nanochitosan/starch loading with ampicillin against E.coli was 95.41%, higher than the 91.40% effectiveness of ampicillin at the same concentration of 5.0 µg/mL after 24 h of treatment. These results suggest that chitosan/starch nanocomposites are potential nanomaterials for antibiotic drug delivery in the pharmaceutical field.
