Aim: Efficacy of antibiotics in cystic fibrosis (CF) is compromised by the poor penetration through mucus barrier. This work proposes a new 'nano-into-micro' approach, used to obtain a combinatorial effect: achieve a sustained delivery of tobramycin and overcome mucus barrier.
Methods: Mannitol microparticles (MPs) were loaded with a tobramycin polymeric nanocomplex and characterized in presence of CF artificial mucus.
Results & discussion: MPs are able to alter the rheological properties of CF artificial mucus, enhancing drug penetration into it and allowing a prolonged drug release. MPs resulted to be effective in Pseudomonas aeruginosa infections if compared with free tobramycin.
Conclusion: MPs resulted to be a formulation of higher efficacy, with potential positive implications, as lower required dose, administration frequency, side effects and antibiotic resistance problems.
Keywords: Pseudomonas aeruginosa infections; cystic fibrosis artificial mucus; mannitol; microparticles; nano into micro strategy; spray dryer; tobramycin; α,β-poly(N-2-hydroxyethyl)-D,L-aspartamide.