Efavirenz Loaded Nanostructured Lipid Carriers for Efficient and Prolonged Viral Inhibition in HIV-Infected Macrophages

Background: The clinical outcome of anti-HIV therapy is poor due to the inherent fallouts of anti-HIV therapy. It is further worsened due to the presence of viral reservoirs in immune cells like the macrophages. An ideal anti-HIV therapy must reach, deliver the drug and exert its action inside macrophages. To address this, we developed novel cationic nanostructured lipid carriers of efavirenz (cationic EFV-NLC). Methods: The developed cationic EFV NLCs were evaluated for particle size, zeta potential, encapsulation efficiency, in-vitro drug release, DSC, XRD, TEM, cytotoxicity, cellular uptake studies and anti-HIV efficacy in a monocyte-derived macrophage cell line (THP-1). Results: Cationic EFV-NLCs showed high encapsulation efficiency (90.54 ± 1.7%), uniform particle size distribution (PDI 0.3-0.5 range) and high colloidal stability with positive zeta potential (+23.86 ± 0.49 mV). DSC and XRD studies confirmed the encapsulation of EFV within NLCs. Cytotoxicity studies (MTT assay) revealed excellent cytocompatibility (CC50 13.23 ± 0.54 μg/mL). Fluorescence microscopy confirmed the efficient uptake of cationic EFVNLCs, while flow cytometry revealed time and concentration dependant uptake within THP-1 cells. Cationic EFV-NLCs showed higher retention and sustained release with 2.32-fold higher percent inhibition of HIV-1 in infected macrophages as compared to EFV solution at equimolar concentrations. Interestingly, they demonstrated 1.23-fold superior anti-HIV efficacy over EFVloaded NLCs at equimolar concentrations. Conclusion: Cationic NLCs were capable of inhibiting the viral replication at higher limits consistently for 6 days suggesting successful prevention of HIV-1 replication in infected macrophages and thus can prove to be an attractive tool for promising anti-HIV therapy.