Used In Biomaterials And Tissue Engineering In Alginate Quality Control Study

Alginates are usually derived from brown algae in which they occur as gels with sodium and calcium. Sodium alginate refers to the polysaccharides of 1-4 glycosidically linked β -D-mannuronic acid (M) and α -L-guluronic acid (G) residues. The relative amount of the two uronic acid monomers and their sequential arrangement along the polymer chain vary widely, depending on the origin of the alginate. The presence of calcium is believed to result in the formation of an "egg-box" structure, with Ca²⁺ ions forming junctions between blocks of guluronic acid residues on adjacent chains.Sodium alginate as a kind of degradable biomedical materials, is more and more popular in the field of tissue engineering. Like the most liquid gel, the function of the sodium alginate depends on its chemical composition and structure. The quality control of the sodium alginate was already involved in the Pharmacopoeia of the United States (USP) and British Pharmacopoeia (BP). It's important to establish the standards of the quality control of the sodium alginate in our country.My research field included two parts.One part is to draft out the standards of the sodium alginate, which is intended for use in biomedical and tissue-engineered medical products. Besides, it also involved the validation for some experimental items of the quality control. In this study the average molecular weight and the molecular weight distribution have been studied by SEC-MALLS. According to the method of ¹H- NMR written in the standards of ASTM, some detailed information were obtained, particularly with regard to the block structure of the sodium alginate, such as Fg, the M/G ratio and N_g>1.The second part is about the sodium alginate microspheres. My research work is trying to established a HPLC method of determination of the drug's contents, and evaluate its in vitro release characteristics for 28 days. There are three kinds of sodium alginate microspheres including paclitaxel, danazol and retinoic acid. The in vitro release measurement was carried out at pH 7.4 and 37 °C in phosphate-buffered saline (PBS) with...