Cell-penetrating self-nanoemulsifying drug delivery systems (SNEDDS) for oral gene delivery

ABSTRACT

Objective: The aim of study was to investigate whether cell-penetrating peptides could amplify cellular uptake of plasmid DNA (pDNA) loaded self-nanoemulsifying drug delivery systems (SNEDDS) by mucosal epithelial cells, thereby enhancing transfection efficiency.

Methods: HIV-1 Tat peptide-oleoyl conjugate (TAT-OL) was synthesized through amide bond formation between HIV-1 Tat-protein 49–57 (TAT) and oleoyl-chloride (OL). SNEDDS formulation contained 29.7% each of Cremophor EL, Capmul MCM and Crodamol, 9.9% propylene glycol and 1% TAT-OL. SNEDDS with OL instead of TAT-OL served as control.

Results: Fluorescent-microscopy demonstrated 0.5% (m/v) nanoemulsions were suitable for subsequent studies. Mucus diffusion of nanoemulsion loaded with fluorescein diacetate (FDA) was 1.5-fold increased by incorporation of TAT-OL. Confocal microscopy confirmed that droplets of nanoemulsions were successfully internalized. Furthermore, quantitative analysis showed that addition of TAT-OL increases uptake of nanoemulsions by 2.3- and 2.6-folds after 2 and 4 hours of incubation, respectively. Cellular internalization pathways were found with substantial decrease in uptake in presence of indomethacin and chlorpromazine. Transfection efficiency investigated on HEK-293-cells was found to be 1.7- and 1.8-fold higher for SNEDDS loaded with TAT-OL compared to Lipofectin and control, respectively.

Conclusion: In comparison to prevailing lipid and polymer-based delivery systems, these novel cell-penetrating SNEDDS likely represent most effective, simplistic and expedite dosage form for mucosal gene delivery.

KEYWORDS:

• Cell-penetrating peptide
• HIV-1 Tat protein
• SNEDDS
• cellular internalization
• transfection efficiency

Declaration of interest

The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.

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Funding

The authors are thankful and would like to extend acknowledgement to the Higher Education Commission of Pakistan (HEC) and the Austrian Agency for International Cooperation in Education and Research (ÖAD) for their support and funding (ICM-2014-09718).