Studies On The Micro-, Nano-Materials Based On Polysaccharide Derivatives For Drug Carrier

The micro-, nano-material based on polysaccharide derivatives with good biocompatibility, is a kind of new drug carrier, which has important application in slow release and controlled release of drugs. The preparation, properties and application of the micro-, nano-materials for drug carrier based on the derivatives of dextran, starch andβ-cyclodextrin were carried out in this thesis.First of all, dextran amino esters were prepared by chemical modification of dextran by amino acid groups, such as lactamine, tryptophan, valine and so on. Among them, dextran propionate tryptophanate (DPT) could self-assemble to be uniform hollow nanospheres in DMAc/H2O, with particle diameter at 80 - 500 nm and shell-thickness at 15 - 100 nm. However, the dialysis system of organic solvents and water had a great influence on the size and morphology of these nanospheres. The size distribution of the prepared nanospheres was from 57 nm to 670 nm in six different organic solvents such as DMSO, DMF, THF and so on. Moreover, the stablity of these hollow nanospheres was also studied to confirm that these hollow nanospheres were stable in deionized water for 2 months both at 25℃and 37℃. These conclusions indicated that DPT was a good amphoteric material, which could self-assemble to be stable hollow nanospheres for the application in drug carrier.Secondly, nano-sized flake carboxymethyl cassava starch (CMCS) with the size at 100 - 400 nm, was prepared via carboxymethylation under ultrasonic irradiation. And the effect of reaction parameters on the substitution degree of carboxymethylation value of CMCS was also studied, including the influence of the molar ratio of NaOH/starch, the molar ratio of Monochloroacetic acid (MCA)/starch, reaction temperature, ultrasonic power and sonication time. Furthermore, starch-dextran grafting was perpared based on CMCS and dextran. And the synthetic technology of amount of triethylamine, reaction time and reaction temperature was optimized. In addition, solid dispersions were prepared using CMCS and starch-dextran grafting as accessories, and the morphology and dispersion property of solid dispersions was studied.Lastly, radial microsphere ofβ-cyclodextran assembly with size at 5 - 30μm was prepared by self-assembling induced by small organic molecules. The influence of different small organic molecules and precipitated solvents on the morphology of assembly was also investigated. In addition, the inclusion of the radial microsphere ofβ-cyclodextran assembly with porphyrin derivative was studied to show that the inclusion ability ofβ-cyclodextran assembly was much better than that ofβ-cyclodextran.