Chitosan (CS) has gained considerable attention due to its distinctive properties and its broad spectrum of potential applications, spanning cosmetics, pharmaceuticals, and biomedical uses. In this study, we characterized thin films comprising chitosan mixtures containing salicin (SAL) and glycerin (GLY), both with and without hyaluronic acid (HA) as active ingredients. Characterization was achieved through release studies of SAL, infrared spectroscopy, microscopy techniques (AFM and SEM), and thermogravimetric analysis (TGA). CS/GLY/SAL and CS/GLY/SAL/HA mixture films were fabricated using the solvent evaporation technique. We probed interactions between the components in the chitosan mixtures via infrared analysis. The concentration of released salicin was monitored at various time intervals in a phosphate buffer (PBS) at pH 5.5 using HPLC. The linear regression analysis for the calibration graph showed a good linear relationship (R2 = 0.9996) in the working concentration range of 5-205 mg/dm3. Notably, the release of SAL reached its peak after 20 min. Furthermore, the introduction of HA caused changes in the films' morphology, but their roughness remained largely unchanged. The results obtained were compared, indicating that the release of SAL in the CS mixture films is sufficient for diverse applications, including wound-healing materials and cosmetic beauty masks.
Keywords: chitosan; hyaluronic acid; release process; salicin; surface properties.