Preparation And Characterization Of Grafted Chitosan Nanoparticles As Drug Delivery Systems

Nanoparticle drug delivery systems may prove superior owing to their high drug loading capacity, controllable size and permeability, and improve the targeting ability, controlled release,controltablility and intellegence of the drugs. Chitosan is a naturally occurring cationic polysaccharide with good biocompatibility, biodegradation, low immunogenicity and non-cytotoxicity. Chitosan nanoparticles have been applied widely in pharmaceutics in recent years and showed to be prospective drug delivery carriers. Chitosan graft copolymer nanoparticles were successfully synthesized in aqueous solution by using as an effective initiator under mild temperature. The preparation and properties of the nanoparticles were investigated.The chitosan-graft-poly(methyl methacrylate) copolymers nanoparticles and chitosan-graft-poly(vinyl acetate) were synthesized in aqueous solution by using potassium diperiodatocuprate [Cu(III)] as an initiator. The effect of reaction conditions such as Cu(III) concentration, reaction temperature and the weight ratio of MMA/CS on the mean particle size was investigated. The nanoparticles were characterized in terms of particle size, zeta potential, transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), thermal stability and X-ray diffraction spectrometry. The results indicated that chitosan was covalently linked to poly(methyl methacrylate) (PMMA) or poly(vinyl acetate) (PVAc) and the resulting copolymers formed nanoparticles. These nanoparticles [prepared at 35°C, in a weight ratio of MMA/CS of 5:1 and with a Cu(III) concentration of 2.0×10–3 mol/L] were 54–350 nm in size, and were highly uniform in particle-size distribution, with a rather spherical shape and an obvious positive charge surface. Insulin-loaded nanoparticles were prepared, and their maximal encapsulation efficiency was up to 90%. The experiment of release in vitro showed that the nanoparticles gave an initial burst release followed by a slowly sustained one.The chitosan-graft-poly(vinyl acetate) copolymers nanoparticles were synthesized by using potassium diperiodatonickelate (IV) as an initiator. The nanoparticles were discrete and uniform spheres, covered with positive charges. The effect of feed ratio of vinyl acetate to chitosan, the initiator concentration and reaction time on the particle size of nanoparticles was investigated. Curcumin nanoparticles were synthesized via ultrasonic irradiation. The encapsulation capability of the nanoparticles and the in vitro curcumin release were studied. Results: The encapsulation efficiency of nanoparticles was up to 91.6%. The in vitro release profile showed the slower release rate of curcumin. The nanoparticles possessed good physical performance and sustained release character in vitro. Paclitaxel nanoparticles were prepared through ultrasonic irradiation technology. The encapsulation capability of the nanoparticles and the in vitro paclitaxel release were studied. The encapsulation efficiency of nanoparticles was up to 93.6%. The in vitro release profile showed the slower release rate of paclitaxel.The film was prepared with chitosan and a mixture of chitosan and nanoparticles respectively; the constituents of curcumin, rhein, emodin, chrysophanol, berberine in the film were determined with HPLC. The release rate of Rhein in film preparaed with chitosan and nanoparticles was better than that of former film.