Preparation and physicochemical characterization of chitosan–sodium tripolyphosphate nanoparticles encapsulating methanol Rosmarinus officinalis extract for controlled bioactive delivery
Rosmarinus officinalis exhibits significant antioxidant activity, though its poor bioavailability limits its practical use. In this study, R. officinalis was extracted with methanol and encapsulated in chitosan–sodium tripolyphosphate nanoparticles (RCSN) at ratios of 1:0, 1:1, 1:2, and 1:3 (RCSN1–RCSN4) to improve efficacy. Thus, the nanoencapsulated extracts were characterized and evaluated for encapsulation efficiency (EE%), differential scanning calorimetry (DSC), Fourier-transform infrared (FTIR), particle-size analysis, in vitro bioactive extract release, and in vivo tests. Flavonoids and phenolics were the highest phytoconstituents. EE (%) ranged from 51% to 85%. FTIR spectrum and DSC depicted functional group consistency and decreased crystallinity, respectively. The particle size distribution indicates particle homogeneity and uniformity, with a polydispersity index of 0.434. The in vitro study demonstrated a controlled-release profile, with the highest release of 60% (RCSN2). The in vivo study of the RCSN showed higher antioxidant activity (10.814 IU/L) compared with the other extracts. The RCSN formulation exhibited sustained release and promising antioxidant potential.