Preparation and In Vitro Characterization of Quercetin and Chlorhexidine-loaded PLGA Nanoparticles for Oral...

This study aimed to develop and evaluate a dual-drug-loaded PLGA nanoparticle system incorporating quercetin (QUE) and chlorhexidine (CHX) for localized, sustained delivery, with potential application in biofilm-associated pathologies.

Single- and dual-drug systems containing CHX and QUE at different concentrations (1.5%, 5%, and 15%) were successfully loaded into poly(lactic-co-glycolic acid) nanoparticles (PLGA NPs) with high encapsulation efficiency. Physicochemical characterization was performed using dynamic light scattering (DLS), zeta potential analysis, SEM-EDX, FTIR, and thermal analysis (DSC and TGA). Release kinetics of QUE- and CHX-loaded nanoparticles were evaluated in an artificial saliva environment, and the amounts of CHX and QUE released were quantified by high-performance liquid chromatography (HPLC). Antimicrobial activity was assessed against Staphylococcus aureus and Escherichia coli using the disc diffusion method.

The prepared nanoparticles displayed spherical morphology with sizes ranging from 54.08 to 356.1 nm and zeta potentials from - 2.11 to -12.46 mV, indicating colloidal stability. FTIR and thermal analysis confirmed molecular dispersion of drugs and polymer-drug interactions. QUE showed complete release within 168 h in the single-drug system, whereas co-loading with CHX extended QUE retention, with 20% remaining after 240 h. CHX release reached ∼80% in both formulations. CHX/QUE nanoparticles demonstrated superior antibacterial activity compared to QUE-only systems, effectively inhibiting both Gram-positive and Gram-negative bacteria.

These compounds and formulations are designed for clinical applications due to their slow, controlled release of the dual-active PLGA NP system.