Silibinin-Loaded Amphiphilic PLGA–Poloxamer Nanoparticles: Physicochemical Characterization, Release Kinetics, and Bioactivity Evaluation in Lung Cancer Cells

Despite its potential against several carcinomas, the pharmacological efficacy of silibinin (SLB) is hampered by poor solubility, absorption, and oral bioavailability. To face these issues, we developed polylactic-co-glycolic acid (PLGA) nanoparticles (NPs) coated with hydrophilic polyethene oxide (PEO) for controlled and targeted SLB delivery. NPs were produced at two different SLB loadings and presented a spherical shape with smooth surfaces and stable size in water and cell culture medium. The encapsulation efficiencies were found to be >84%, and thermal analysis revealed that the SLB was present in an amorphous state within the NPs. In vitro SLB release experiments revealed that at the lowest SLB loading, desorption of the active molecule from the surface or nanoporosities of the NPs mainly dictates release. In contrast, at the highest SLB loading, diffusion primarily regulates release, with negligible contributions from other mechanisms. Cell experiments showed that, compared with the free drug, SLB loaded in the produced NPs significantly increased the bioactivity against H1299, H1975, and H358 cells.