Development and Characterization of Lyophilized Gentamicin-Loaded Liposomes: From Storage Stability to Electroporation-Enhanced Release

This study investigated the development, characterization, electroporation-triggered drug release, and storage stability of lyophilized gentamicin sulfate (GS)-loaded liposomes produced by microfluidics. The effect of lyophilization and reconstitution on physicochemical properties and encapsulation efficiency was assessed, followed by comparison of two formulations (3:1 and 5:1 flow-rate ratios) to select a formulation for further investigation. The selected 5:1 formulation was evaluated for in vitro gentamicin release following electroporation at 0, 160, 200, and 250 V under different pH and release-media conditions. Long-term stability was assessed at 4°C, room temperature, 37°C, and −20°C for up to three months using DLS, NTA-PRO, and VideoDrop. Lyophilization caused no significant reduction in gentamicin encapsulation efficiency, while the 5:1 formulation demonstrated greater early drug release and was selected for subsequent studies. Electroporation promoted earlier gentamicin release, particularly at 250 V, with release behavior also influenced by environmental conditions. During storage, particle characteristics, particle concentration, and gentamicin retention progressively changed, with 4°C generally providing the most favorable preservation. Overall, these findings support further development of lyophilized GS-loaded liposomes as an electrically responsive drug-delivery platform.