Development of curcumin-loaded ethyl cellulose–sodium alginate/chitosan microgels for bactericidal applications

A novel ethyl cellulose-sodium alginate/chitosan/curcumin (EC-SA/CS/Cur) composite microgel system was developed through a one-step emulsion method. Optimized homogenization at 1,300 rpm for 2 min enabled consistent fabrication of EC-SA/CS/Cur microgels with a mean particle size of 2.85 μm. The microstructural morphology, particle size distribution, and chemical composition of the optimized EC-SA/CS/Cur microgels were characterized by microscopy, laser particle size analysis, and Fourier-transform infrared spectroscopy. The microgels exhibited a curcumin encapsulation efficiency of 54.4 ± 6.8% and a drug loading capacity of 0.032 ± 0.004%. The microgels exhibited excellent stability under enzymatic and physiological pH environments while displaying a unique sustained-release profile in ethanol-containing media; under agitated conditions, a cumulative release of 3.2 μg/mL was achieved within 6 h, representing a 28.0% increase in cumulative release compared to static conditions. The minimum inhibitory concentration of EC-SA/CS/Cur microgels was determined as 675 μg/mL; after 3 h of exposure, their antimicrobial efficacy significantly outperformed free curcumin. These results confirm that the EC-SA/CS microgel system acts as an effective delivery vehicle, markedly enhancing curcumin’s antimicrobial performance. This study provides a promising strategy for developing stable, high-efficiency curcumin delivery systems with improved therapeutic potential, particularly for oral/throat protection against alcohol-induced irritation via on-site curcumin release to alleviate local inflammatory damage.