Abstract
<title>Abstract</title> <p> The global emergence of antimicrobial resistance has driven the development of novel strategies for the treatment of bacterial infection. In this context, Dextran-based Single-Chain Polymeric Nanoparticles (DXT-SCPN) have been developed as antibiotic delivery systems for the treatment of pulmonary infections. A series of DXT-SCPN with different physicochemical properties, namely varying degrees of substitution: low (L-DS <sub>apry</sub> ), medium (M-DS <sub>apry</sub> ), and high (H-DS <sub>apry</sub> ) and different crosslinking degrees: medium (M-DS <sub>apry</sub> ) and high (H-CL <sub>apry</sub> ), were formulated with apramycin to evaluate the <italic>in vitro</italic> activity against eleven <italic>Acinetobacter baumannii</italic> clinical isolates. Minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC) and Time-Kill kinetic (TKK) assays were performed to assess the antibacterial activity of the formulated apramycin in comparison with the free drug. Overall, no statistically significant differences were observed among the antimicrobial activity of free and formulated apramycin. Nevertheless, a slight trend towards higher activity in the case of M-DS <sub>apry</sub> and H-CL <sub>apry</sub> was observed. </p>