Protein-Loaded Solid Lipid Nanoparticles: A Novel Delivery Platform for Enhanced Bioavailability

Abstract

Introduction: Lactoferrin (LF)-loaded solid lipid nanoparticles (SLNs) enhance LF’s stability, bioavailability,
and targeted anticancer activity by protecting it from degradation and enabling receptor-mediated delivery to
tumor cells. This nanocarrier system offers a promising strategy for effective and safe cancer prevention and
therapy. Methodology: A standard curve for LF was established by measuring the absorbance of serial dilutions
at 465 nm, showing linearity confirmed by a high correlation coefficient (R2
) using linear regression analysis. The
infrared spectra confirmed the presence of characteristic functional groups of LF, poloxamer, and the optimized
formulation F6, indicating successful incorporation of both components without major structural alterations.
LF-loaded SLNs were successfully formulated via homogenization–ultrasonication, producing nanosized particles
(30–100 nm) with mannitol as a cryoprotectant during lyophilization. Results and Discussion: LF-loaded SLN
formulations showed optimal entrapment efficiency (50.61–58.01%) at specific lipid and surfactant concentrations,
with efficiency influenced by lipid-to-surfactant ratio and surfactant-induced surface coverage. The polydispersity
index (PDI) of LF-loaded SLNs indicated narrow size distribution and good stability, with particle size and PDI
increasing alongside glyceryl behenate concentration. Zeta potential analysis using Horiba SZ-100 confirmed the
stability of optimized LF-loaded SLNs, with a high surface charge preventing aggregation and ensuring uniform
dispersion. In vitro release kinetics of optimized LF-loaded nanoparticles best fit the Higuchi model (r2
= 0.9619),
indicating diffusion-controlled release from the lipophilic matrix. Conclusion: The study indicates that the
nanocarrier system offers a viable and successful method for LF delivery in cancer treatment and prevention.