pH-responsive and porous vancomycin-loaded PLGA microspheres: evidence of controlled and sustained release for localized inflammation inhibition in vitro

Abstract

Adequate delivery of antibiotics to infected sites is crucial for the effective treatment of bacterial infections. A controlled and sustained release system based on porous and pH-responsive poly(lactic-co-glycolic acid) (PLGA)–vancomycin (Van) microspheres was developed. In this system, drug release is triggered by the weakly acidic environment, like local inflamed tissues. The microspheres, developed through the W₁/O/W₂ double-emulsion evaporation method, comprised a PLGA-based shell and a core containing Van and the bubble-generating agent of NaHCO₃. The optimized preparation conditions for PLGA–NaHCO₃–Van microspheres were investigated and characterized. The PLGA–NaHCO₃–Van microspheres exhibited porous microstructures with regular shape and uniform size and the characteristic of controlled drug release, which could be attributed to the incorporation of NaHCO₃. The results of the Kirby–Bauer assay confirmed that released Van retained effective antibacterial activity towards standard Staphylococcus aureus and methicillin-resistant S. aureus (MRSA) infected clinical samples, suggesting their further promising application in local anti-infection.