The Formulation and Evaluation of Salicylic Acid- Loaded Polymeric Nanoparticles using Eudragit Rs-100 for Antibacterial Activity

Abstract

The present study investigates the formulation and evaluation of salicylic acid-loaded polymeric nanoparticles using Eudragit RS-100, prepared via the solvent evaporation method. This approach involved emulsification, solvent removal, and lyophilization, resulting in nanoparticles designed for enhanced antimicrobial and anti-biofilm performance. Comprehensive physicochemical characterization was performed, including particle size analysis, zeta potential measurement, entrapment efficiency, and morphological assessment via scanning electron microscopy (SEM). The nanoparticles exhibited sizes ranging from 97.23 to 342.22 nm, with F4 formulation demonstrating the smallest average particle size. Zeta potential values (−0.1 to +5.3 mV) indicated colloidal stability, while entrapment efficiency ranged from 68.16% to 92.33%, with F4 again showing the highest encapsulation. Antibacterial activity was assessed against Bacillus subtilis (Gram-positive) and Pseudomonas aeruginosa (Gram-negative) using the agar well diffusion assay. The nanoparticles displayed notable zones of inhibition, with F4 formulation achieving the highest antibacterial efficacy. Anti-biofilm activity was further evaluated using the test tube assay and quantified via crystal violet staining and spectrophotometry. Results demonstrated substantial biofilm inhibition at higher concentrations (125 µg/mL), highlighting the nanoparticles' ability to impede bacterial adhesion and biomass formation. These findings underscore the potential of Eudragit RS-100-based polymeric nanoparticles as a viable platform for controlled drug delivery and effective antimicrobial interventions, particularly in targeting resistant bacterial strains and biofilm-associated infections.