Long-term release and improved intracellular penetration of oligonucleotide-polyethylenimine complexes entrapped in biodegradable microspheres.
The aim of this work was to design a biodegradable delivery system for oligonucleotides providing both a sustained release and an improved intracellular penetration. To this purpose oligonucleotide/polyethylenimine (ON/PEI) complexes at nitrogen to phosphate (N/P) molar ratios of about 15 or 40 were encapsulated into poly(lactide-co-glycolide) microspheres by the multiple emulsion-solvent evaporation technique. ON/PEI complexes were efficiently entrapped inside microspheres. The introduction of salts within the external aqueous phase allowed an improvement of microsphere characteristics. In particular, the use of sodium chloride led to a reduced microsphere porosity and a more homogeneous ON distribution inside the polymeric matrix. These effects were attributed to the reduced flux of water from the external aqueous phase toward the internal aqueous droplets, due to the osmotic effect of sodium chloride. Both, the reduced porosity and the improved ON distribution inside the matrix, were considered responsible for the lower burst effect and the slower ON release rate from microsphere prepared with sodium chloride. ON/PEI complexes encapsulated inside microspheres were also protected toward enzymatic degradation in fetal calf serum. Interestingly, ON/PEI complexes slowly released from microspheres efficiently penetrated inside HeLa cells and oligonucleotides were preferentially located in the nucleus.
De Rosa
Giuseppe
G
UMR CNRS 8612, Group of Drug Targeting and Delivery of Poorly Stable Compounds, Université Paris-Sud, 5, rue Jean-Baptiste Clément, 92296 Châtenay-Malabry, France.
Quaglia
Fabiana
F
Bochot
Amélie
A
Ungaro
Francesca
F
Fattal
Elias
E
D001673:Biodegradation, Environmental; D003692:Delayed-Action Preparations / Q000493:pharmacokinetics; D006367:HeLa Cells; D006801:Humans; D007424:Intracellular Fluid / Q000378:metabolism*; D009841:Oligonucleotides / Q000493:pharmacokinetics*; D011094:Polyethyleneimine / Q000493:pharmacokinetics*
D003692:Delayed-Action Preparations; D009841:Oligonucleotides; D011094:Polyethyleneimine