OICC Press International Journal of Nano Dimension 2228-5059 16 4 2025 05 28 A novel approach for oral delivery of ZINC using Zinc Sulfate solid lipid nanoparticles 10.57647/j.ijnd.2025.1604.28 EN Zahra Inanloo Department of Chemistry, Science and Research Branch, Islamic Azad University, Tehran, Iran Mohammad Yousefi Department of Chemistry, Faculty of Pharmaceutical Chemistry, Tehran Medical Sciences, Islamic Azad University, Tehran, Iran Sahar Baniyaghoob Department of Chemistry, Science and Research Branch, Islamic Azad University, Tehran, IranSahar Baniyaghoob https://orcid.org/0000-0001-6942-6796 Journal Article 2025 05 28 One potential tool to improve the absorption of zinc (Zn) is the use of solid lipid nanoparticles (SLNs). In this study, Zn-containing SLNs were prepared to explore a novel oral formulation and investigate its physicochemical properties, toxicity, and accelerated stability study. SLNs were fabricated using stearic acid as lipid and chitosan as coating for LNPs via double emulsion solvent evaporation followed by lyophilization. In vitro evaluations were performed before and after lyophilization. Zinc loading was optimized at 30% zinc (w/w) versus lipid, with drug loading efficiency (DL) of up to 90%. The physicochemical properties of Zn-SLNs, including particle size (from 83.7 ± 1.8 to 183.8 ± 5.0 nm), dispersion index (PDI), zeta potential (about 8.2 mV), and differential scanning calorimetry (DSC), were investigated. Morphological characteristics were evaluated using scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray diffraction (XRD). Drug release studies showed that 75%, 83%, and 90% of zinc were released from the SLN-Zn-Chitosan formulation within 24 hours, respectively. A cytotoxicity assay (MTT) performed at 24, 48, and 72 hours showed no cytotoxic potential with cell viability at 100% of control cells. The accelerated stability study to evaluate particle size, zeta potential, and drug loading (%EE) at 6 months showed no significant changes, which could indicate the suitability of Zn-SLNs for oral applications.