Box-Behnken-designed nanostructured lipid carriers of xanthohumol for enhanced cellular uptake in human lung cancer cell line A549: formulation, optimization, characterization, and cytotoxicity assessment

The present research aims to develop and optimize nanostructured lipid carriers (NLCs) of Xanthohumol (Xn) for treating lung cancer (LC). Xn packed NLCs were successfully prepared by hot high-pressure homogenization in conjunction with the ultrasonication method and optimized using a pseudo-ternary phase diagram followed by the Box-Behnken design (BBD). The NLCs were solidified using rotary evaporation followed by tray drying/vacuum drying. Mannitol was used for the solidification of L-Xn-NLCs. The BBD was operated using 3 factors and 3 levels for optimization of the formulation. The dependent variables were zeta potential (R1), particle size (R2), and drug entrapment efficiency (R3), while the independent variables were Beeswax (A), Lauroglycol-90 (B), and Tween 80 (C). The optimized liquid NLCs (L-Xn-NLCs) showed particle size (PS) of 101.60 ± 1.47 nm, polydispersity index (PDI) of 0.772 ± 0.029, zeta potential (ZP) of - 25.6 mV, and an entrapment efficiency (% EE) of 97.72 ± 1.05%. As a result, NLCs have a higher drug encapsulation efficiency. After drying, followed by reconstitution, the solid NLCs (S-Xn-NLCs) showed PS of 278 nm, PDI of 0.22, ZP of - 44.3 mV, and EE% of 95.5. The results of SEM and PXRD revealed the complete adsorption of S-Xn-NLCs on the surface of mannitol. The in vitro drug release and in vitro MTT assay were performed on A549 LC cells to evaluate the anticancer efficacy of S-Xn-NLCs. In 24 h, the L-Xn-NLCs, S-Xn-NLCs, and pure drug suspension had a cumulative drug release rate of 80.09 ± 0.8%, 79.8%, and 40 ± 1.1%, respectively. It was found that both pure Xn and S-Xn-NLCs reduced the proliferation of A549 cell lines at 28.21 µM, 56.42 µM, 84.63 µM, 112.84 µM, and 141 µM. However, S-Xn-NLCs exerted higher reduction in proliferation than pure Xn. The pure Xn and the S-Xn-NLCs showed anticancer potential against A549 cell lines and the IC50 was found to be 140.186 µM for the pure Xn and 84.63 µM for the S-Xn-NLCs. The S-Xn-NLCs showed higher cytotoxicity potential to A549 cells as compared to the pure Xn. Thus, it was concluded that the optimized NLCs showed very good efficacy against LC.