Preparation Of Hydrophobically Modified Chitosan Nanoparticles As Carriers For Anticancer Drug

Chitosan, a natural polysacchairide, is the only alkalinous polyose which widely exiting in the living nature. It is an N-deacetylated derivative of chitin. It has biocompatibility, hypotoxicity, biodegradation ability and hardly has any sensibilization, so it has a lot of medical function and durg action. But chitosan is only dissolved in some organic acid, therefore its application is limited. In order to expand its application and develop new compounds which have good nature, various studies of the chemical modification of chitosan are necessary.To make chitosan having PH sensitivity, in this paper chitosan was grafted by sulfadimethoxypyrimidine (SDM) which is a pH sensitivity group. Firstly, N-succinyl-chitosan was synthesized by ingrafting succinic anhydride to chitosan. In this experiment, succinic anhydride not only played an important bridge part between chitosan and SDM, but also increased the water-solubility of chitosan to promote the form of nanoparticle. Then N-succinyl-chitosan was grafted by SDM to get objective product HCS. HCS was formed into nanoparticle in phosphate buffer saline (pH=9.18) by self-assembly method. The analysis methods of HCS were Fourier infrared spectrum,nuclear magnetic resonance and elemental analysis, the results showed that SDM was successfully ingafted to chitosan. The surface nature and particle diameter of HCS nanoparticles were analyzed with scanning electron microscope,transmission electron microscope and dynamic light scattering, and the results showed that the appearance of nanoparticles is good and the disposition of particle diameter is rather centered. In addition, the research to physical stability of HCS nanoparticles showed that the disposition of particle diameter did not change a lot while the environmental factor changed. The results of disposition of particle diameter in nanoparticles solution with different pH showed that the particle diameter increased uninterruptedly while the pH decreased. This demonstrated that the nanoparticles formed by self-assembly method after SDM was ingrafted to chinosan had good pH sensitivity nature. Eventually 5-Fu was taken as model drug, and the HCS physically enveloped the drug to nanoparticles by self-assembly in the PBS(pH=9.18). The experiment showed that loading content and loading efficiency of HCS nanoparticles is really good. Also, the HCS nanoparticles showed good delayed release effect, and had good pH sensitivity--the delayed release effects were different at different pH. In consequence, the HCS nanoparticle is suitable to load anticancer drugs.