Targeted Nanostructured Lipid Carriers of Erlotinib using Transferrin for Enhanced Brain Delivery in Glioblastoma: Formulation and BBD-Based Optimization

Abstract

Glioblastoma is an aggressive form of brain cancer with limited treatment therapies due to the Blood-Brain Barrier (BBB), which makes it challenging for most medications to cross it and the difficulty of achieving tumour-specific targeting. Transferrin receptors (TfR) are overexpressed on endothelial cells of the blood-brain barrier and glioblastoma cells, enabling transferrin (Tf) conjugation for receptor-mediated targeting. This study developed and optimized erlotinib-encapsulated nanostructured lipid carriers (NLCs) using a DoE software, Box-Behnken design (BBD), to enhance targeted glioblastoma treatment. The emulsification-solvent evaporation technique is used to formulate the NLCs. The optimized NLCs showed high entrapment efficiency (89.62%), drug loading (14.62%), particle size (167.9 nm), PDI (0.32), zeta potential (−27.36 mV), and sustained release of drug from the lipid matrix. The FTIR and DSC characterization confirmed no interaction between the drug and the formulation’s excipients, as well as the amorphous drug dispersion in the lipid matrix. SEM and TEM confirmed that the spherical particles are uniformly dispersed. The Tf-conjugation was confirmed by 1H NMR spectroscopy and coupling efficiency. Erlotinib-loaded NLCs exhibited potential anticancer activity with an IC50 value of 15.3 μg/mL compared to the free drug, whereas Tf-Erlo-NLCs demonstrated a significantly higher efficacy IC50 i.e., 6.25 μg/mL. Tf-Erlo-NLCs significantly increased cellular uptake (31.96 ± 1.39%) compared to unconjugated NLCs (13.25 ± 0.48%), confirming TfR-mediated internalisation. A total of 44.81 ± 1.69% of the cells were apoptotic, with most of them showing early and late apoptosis and very little necrosis (3.58 ± 0.64%), which is a controlled way for cells to die. Erlotinib-loaded NLCs exhibited a potential anticancer effect with a 15.3 μg/mL IC50 value compared to the free drug, whereas Tf-Erlo-NLCs demonstrated a significantly higher efficacy IC50, i.e., 6.25 μg/mL. Tf-Erlo-NLCs significantly increased cellular uptake (31.96 ± 1.39%) compared to unconjugated NLCs (13.25 ± 0.48%), and better permeability (1.5 times) than the standard drug and Tf-Erlo-NLCs in the BBB model hCMEC/D3 cell line, supporting ligand-receptor-facilitated drug uptake. A total of 44.81 ± 1.69% of the cells were apoptotic, with most of them showing early and late apoptosis and very little necrosis (3.58 ± 0.64%), which is a controlled way for cells to die. These results revealed that the Tf-Erlo-NLCs are a potential targeted nanocarrier system for effective delivery of the drug in glioblastoma treatment.