Development and Characterization of Chitosan–Polyvinylpyrrolidone Nanoparticles for Antimicrobial Drug Delivery Applications

Chitosan (CS) and polyvinylpyrrolidone (PVP)-based nanoparticles (NPs) are promising carriers for drug delivery due to their biocompatibility, biodegradability, and intrinsic antimicrobial properties. This study explores CS-PVP NPs for the encapsulation and controlled release of synthetic compounds (bis-THTT, JH1, JH2) and natural antimicrobials (honey and propolis). NPs were synthesized via ionic gelation, optimizing CS:PVP and CS-PVP:sodium tripolyphosphate (TPP) ratios. The optimal formulation (CS:PVP 1:0.5) produced stable, homogeneous NPs. Characterization was performed using FTIR, TGA, XRD, and AFM. Encapsulation efficiencies ranged from 44–60%. Antimicrobial activity was evaluated against Escherichia coli and Staphylococcus aureus, showing significant inhibition for JH1-, JH2-, honey-, and propolis-loaded NPs against E. coli. Cytotoxicity assays on 3T3 fibroblasts confirmed the biocompatibility of all formulations at 5 and 10 µg/mL. In vitro release studies in artificial gastric fluid (pH 1.78) demonstrated sustained drug release over 180 min. These results confirm that CS-PVP NPs can effectively encapsulate and protect both synthetic and natural bioactive compounds, enhancing their therapeutic potential. The developed nanosystems represent a versatile and safe platform for antimicrobial drug delivery and may support future applications in biomedical therapies.