Elaboration of targeted nanodelivery systems based on colloidal polyelectrolyte complexes (PEC) of chitosan (CH)-dextran sulphate (DS)

Abstract

This work reports the first drug nanodelivery system based on polyelectrolyte complexes (PECs) between chitosan (CH) and dextran sulphate (DS), stable in physiological media surface and functionalised by antibodies for drug targeting. The formation of colloidal PECs occurred at room temperature, under moderate stirring, by mixing two water solutions of the polysaccharides, which makes this process attractive for safety and environmental reasons and also for the incorporation of labile molecules. The polymer interactions were characterized by thermal analysis and the morphology was observed by scanning electron microscopy. The resulting particles had a spherical shape with a controlled size distribution (350 – 590 nm, PI = 0.1) and displayed a positive surface charge. They remained stable for 1 month in physiological conditions (PBS pH 7.4), 150 mM NaCl or acidic conditions: 0.1 M citric acid, pH 5. In PBS, the model drug (tenofovir) was quantitatively encapsulated. The antibody sorption onto the PECs was carried out in the buffers used for the particles formulation. We reported that the sorption capacity increased with particles at lower concentration ( < 0.1 wt%). Furthermore, the adsorbed antibodies remained bioactivities, as shown by ELISA, confirming that this formulation is very promising for the development of new delivery systems.