Ampicillin-Loaded Chitosan Nanoparticles for In Vitro Antimicrobial Screening on Escherichia coli

Purpose: To develop ampicillin-loaded chitosan nanoparticles by modified ionic gelation method for evaluating their antimicrobial activity onto Escherichia coli . Methods: Ampicillin-loaded chitosan nanoparticles (CHT-NPs) prepared by ionic gela - tion method with sodium tripolyphosphate as cross-linking agent. Drug release param eters (zeta potential, particle size, entrapment efficiency, and in vitro drug release) were assessed in relation to CHT-NP antimicrobial profile on E. coli . Antibacterial properties of CHT-NP formulation with ampicillin were found better than mere ampicillin without CHT-NPs. Results: SEM, AFM images revealed dimensions of CHT-NPs with irregularity in shape/ size. Optimized concentrations of chitosan 0.5% w/v with three different ratios (0.05% to 0.3% w/v) of TPP proved optimal for the evaluation of antibacterial profile of CHT-NPs. In vitro ampicillin-loaded CHT-NP delivery studies revealed an initial burst followed by slow sustained drug release, demonstrating superior antimicrobial activity than plain ampicillin, due to the synergistic effect of chitosan and ampicillin . Conclusion: Chitosan content and cross-linking agent concentrations are control factors in synthesis of the optimized CHT-NP formulation. CHT-NPs with ampicillin cargo capa bly sustained ampicillin delivery due to NP size and increased surface charge, resulting in efficient growth inhibition in assays with E. coli .