Sorafenib tosylate loaded superparamagnetic nanoparticles: Development, optimization and cytotoxicity analysis on HepG2 human hepatocellular carcinoma cell line

Iron oxide (magnetite) is the core of magnetic nanoparticles, which can be directed to the desired location using an external magnet. In this study, the magnetic nanoparticles were prepared by an emulsion solvent evaporation method and optimized using Box Behnken design. The mean particle size, polydispersity index, and zeta potential of optimized nanoparticles (formulation PMP-11) were 71.81 ± 4.4 to 384.1 ± 10.5 nm, 0.203 ± 0.008 to 0.777 ± 0.010, and −34.4 ± 3.1 to −10.2 ± 0.6 mV, respectively. The entrapment efficiency was found to be 84.64 ± 0.78%. TEM image confirmed formation of spherical nanoparticles. After 24 h, the formulations released 25.18%–56.63% and 54.38%–90.56% of loaded drug in phosphate buffer (6.8 pH) and 0.1 N HCl (pH 1.2), respectively. In HepG2 cell lines, the IC₅₀ value of optimized formulation was recorded to be 38.12 μg/mL. XRD analysis confirmed amorphous form of loaded drug. The mean average surface roughness for magnetite and optimized formulation was found to be 5.27025 nm and 8.29138 nm, respectively. The magnetization saturation for magnetite and optimized was 28.58 emu/g and 25.46 emu/g, respectively. Electron paramagnetic resonance spectroscopy of pure magnetite indicated g-Lande factor of 4.30 (typical for Fe³⁺ ions). The g factor for optimized formulation was 4.24 suggesting superparamagnetic nature of the particles.