Ternary polysaccharide complexes: Colloidal drug delivery systems stabilized in physiological media

Nanoassemblies of Chitosan-Based Polyelectrolyte Complexes as Nucleic Acid Delivery Systems

Nucleic acid delivery requires vectorization for protection from nucleases, preventing clearance by the reticuloendothelial system, and targeting to allow cellular uptake. Nanovectors meeting the above specifications should be safe for the patient, simple to manufacture, and display long-term stability. Our nanovectors were obtained via the green process of polyelectrolyte complexation, carried out at 25 °C in water at a low shear rate using chitosan (a polycationic biocompatible polysaccharide of specific molar mass and acetylation degree) and dextran sulfate as a polyanionic biocompatible polysaccharide. These complexes formed nanoassemblies of primary nanoparticles (20-35 nm) and maintained their colloidal stability for over 1 year at 25 °C. They could be steam sterilized, and a model nucleic acid could be either encapsulated or surface adsorbed. A targeting agent was finally bound to their surface. This work serves as a proof of concept of the suitability of chitosan-based polyelectrolyte complexes as nanovectors by sequential multilayered adsorption of various biomacromolecules.

Chitosan-based Colloidal Polyelectrolyte Complexes for Drug Delivery: A Review

Polyelectrolyte complexes (PECs) as safe drug delivery carriers, are spontaneously formed by mixing the oppositely charged polyelectrolyte solutions in water without using organic solvents nor chemical cross-linker or surfactant. Intensifying attentions on the PECs study are aroused in academia and industry since the fabrication process of PECs is mild and they are ideal vectors for the delivery of susceptible drugs and macromolecules. Chitosan as the unique natural cationic polysaccharide, is a good bioadhesive material. Besides, due to its excellent biocompatibility, biodegradability, abundant availability and hydrophilic nature, chitosan-based PECs have been extensively applied for drug delivery, particularly after administration through mucosal and parenteral routes. The purpose of this review is to compile the recent advances on the biomedical applications of chitosan-based PECs, with specific focuses on the mucosal delivery, cancer therapy, gene delivery and anti-HIV therapy. The challenges and the perspectives of the chitosan-based PECs are briefly commented as well.