Nanoparticles of anionic starch and cationic cyclodextrin derivatives for the targeted delivery of drugs

Starch was oxidized with TEMPO for the synthesis of water-soluble copolymers of glucuronic acid and glucose. The carboxylate groups of these copolymers were conjugated with pteroic acid as cell-specific ligand for targeting to cancer cells. Stable spherical nanoparticles (NPs) were formulated mixing aqueous solutions of the anionic copolymers and of a cationic thioether of β-cyclodextrin (β-CD). Particle size distributions of NPs were investigated with DLS as the function of the charge ratio of the constituents. The smallest and most uniform particles with a diameter of about 130 nm were generated at a charge ratio of anion/cation close to 1, preferably 1.2. Stabilities and particle size distributions of these starch NPs were very satisfactory. The starch/β-CD NPs could be loaded with hydrophobic guest molecules like 1,4-dihydroxyanthraquinone (DHA), which served as a model for the important class of anthracycline antibiotics used in cancer therapy.