Research On Chitosan-based Drug-releasing Materials

Chitosan is a kind of alkalescence amylase which is exclusive, nontoxic, and biodegradable. It is produced by part deacetylation of chitins using alkali or enzyme. Therefore, it can also be called as polysaccharide of amido glucose. After chitin is deacetylated by chemical method, chitosan is solve in weak acid, and its absorptivity is high. The application researches on chitosan are becoming its trend of research and development in the world.Through controlling the drug release rate, the results of suitable drug concentration in the blood, less drug-delivery frequency, lower bad respondence, and increased curative effect have been achieced. This is the trend of research and development in drug manufacture recently. Compared with synthetic materials, chitosan using as the drug release carrier may not only adjust the drug concentration in blood, drug-delivery frequency, and drug stimulation on intestine and stomach, but also take part in the natural metabolism and accumulate nothing in the body.In this article, chitosan is used as the main material. Levofloxacin and Sodium salicylate are choosen as the target drugs. Levofloxacin is the third generation of fluoroquinolones. Its half life is 6 hours, and its capbality of antibiotic is very good. Sodium salicylate has many advantages such as resisting fungus, curing fever, easing pain, and resisting rheumatism.Using alcoholic aldehyde condensation reaction and reverse suspension-crosslink method, the chitosan drug-loaded microsphere, CS/PVA blending microsphere, CS/PAA/PEG complex microsphere were prepared. The brief contents and results are as follows:1. Using reverse suspension-crosslink method, chitosan microsphere and chitosan drug-loaded microsphere were prepared. Those microspheres were characterized by microscope, IR spectrum, UV-4100, and drug dissolution test analyzer. The different influence factors on microsphere quality were discussed and the process was optimized. Finally, the uniform microspheres with good drug loading capability and drug releasing behavior are obtained.2. Through polyer blending method and alcoholic aldehyde condensation reaction, PVA / chitosan microspheres with physical blending and chemical crosslinking structures are prepared. Their structures and properties were characterized by the microscope, IR spectrum, UV-4100, and drug dissolution test analyze. Finally, PVA / chitosan microspheres with physical blending are uniform microspheres about 1～20μm, drug loading capability to 13% and drug releasing percent to 80% in 12 hours. And PVA / chitosan microspheres with chemical crosslinking structures are uniform microspheres about 1.69μm, drug loading capability to 17.1% and drug releasing percent to 100% in 6 hours.3. Using reverse suspension-crosslink method and physical blending method, CS/PEG complex microspheres were synthesized. Their structures and behaviours were characterized by the microscope, IR spectrum, UV-4100, and drug dissolution test analyzer. The process of CS/PEG microsphere was optimized. Finally, CS/PEG complex microspheres are uniform microspheres about 60μm and drug loading capability to 2.61%.4. Using chemical polymerization and physical blending method, CS/PAA/PEG complex microspheres were synthesized. Their structures and behaviours were characterized by the microscope, IR spectrum, UV-4100, and drug dissolution test analyzer. The process of CS/PAA/PEG microsphere was optimized. Finally, CS/PAA/PEG complex microspheres with chemical polymerization are uniform microspheres about 16.1μm and drug loading capability to 3.8%.And CS/PAA/PEG complex microspheres with physical blending method are uniform microspheres about 8.76μm and drug loading capability to 3.0%.