Research On Physical And Chemical Properties Of Mactra Veneriformis And Its Application As Drug Carrier

This work was supported by the National Nature Science Foundation(No:30900293) and the R&D Special Fund for Public Welfare Industry from State Ocean Administration P.R. China (No200705009).Crude polysaccharide,was extracted from Mactra veneriformis by water extraction and alcohol precipitation. Its physical and chemical characterization of polymer in order to enrich the Mactra veneriformis polysaccharide based theoretical system, and the use of physical and modification of polysaccharides to mix chitosan with Mactra veneriformis polysaccharide to produce microsphere which was prepared by spray-drying method. With the hypoglycemic drug-metformin hydrochloride in it to become a good stability of microspheres administered dosage forms. Following parts were mainly included:1.Literature studyResearch papers about the design of drug-loaded microspheres used natural polysaccharide were referred. Especially the most commonly natural polysaccharides such as:sodium alginate, chitosan, agarose, carrageenan, hyaluronic acid, the structure of these natural properties and their microspheres design are were studied, which aims to develop new marine polysaccharide as new carrier material2.The study of powder properties of Mactra veneriformis polysaccharideTCA method was used for removal of protein and further we used dialysis impurity,and its component analysis showed that it contains90%of the total sugar and a small amount of protein and sulfate.Using X-ray diffraction,TG and DSC to analysis the crystal structure of the Mactra veneriformis, the result showed that it has a amorphous structure,with good thermal stability.3.The study of solution properties of Mactra veneriformis polysaccharideTo study the dissolution properties of Mactra veneriformis polysaccharide,we founded that it is soluble in water and almost insoluble in organic solvent.Temperature impact great on its dissolution:as the temperature increasea,its solubility increases.Congo red experiment was used to study the the conformation in aqueous solution which showed that the main chain of Mactra veneriformis polysaccharide is a orderly chain, because of the non-crystalline structure,the solution is generally monodisperse state,without a non-triple-helical structure. By gel permeation chromatography(GPC),we study the stability of the solution of Mactra veneriformis polysaccharide,the results show that in24hours, it does not degrade in the two kinds of crtificial environment; while the DNS method shows that within24hours of interaction with α-amylase,the Mactra veneriformis polysaccharides degrade.4. Preliminary evaluation of biological safety of Mactra veneriformis polysaccharidesDetermination of cell viability by MTS, found that in human normal liver cells and rat fibroblast cell activity the Mactra veneriformis polysaccharides showed no inhibition; also we found high concentrations (250～500mg/ml) Mactra veneriformis polysaccharides in fibroblasts cell showed a certain role in promoting proliferation; hemolysis experiments also show that the non-hemolytic. It can be considered that the Mactra veneriformis polysaccharides can be used as functional materials as well as the tissue engineering research with a broad application prospects.5. Preparation and characteristics of chitosan/MVPS microsphereMetformin hydrochloride microsphere was preparated by spray drying methods of preparation for with mactra quadrangularis polysaccharide (MVPS)and chitosan as raw materials.The optimum technological conditions of metformin hydrochloride micropheres preparation was decided by the orthogonal experiment. Microspheres microcosmic structure and phase and size are analyzed by scanning electron microscope analysis and X-ray diffractioa Results show that the inlet temperature of110℃, air flow rate was44mm,3:1drug material, feed rate of2.7ml·min-1. By UV spectrophotometry under optimal conditions product yield、drug loaded、 encapsulation efficiency were(75.07±2.48)%、(22.31±0.38)%、(89.22±1.53)%, compound loaded microspheres surface is smooth, with an average particle size of4.84μm, narrow particle size distribution, normal distribution; drug was existed as molecular form after the formation of microspheres.