Study On Preparation And Application Of Degradable Starch Microspheres

Soluble starch was taken as raw materials. Degradable starch microspheres (DSMs) were synthesized by the way of reversed-phase emulsion polymerization, and we carries out the research program of DSMs which included preparation, physical and chemical properties and drug loading.Using the diameter of DSMs as response variable, the five variables—the concentration of starch solution, stirring rate, volume ratio of oil phase to water phase, quantity of surfactant, quantity of linker were investigated by single factor design and uniform design. The multiple regression equation was acquired. The equation showed: the greater stirring rate and volume ratio of oil phase to water phase, the smaller the diameter of DSMs.Physical and chemical properties of DSMs were investigated. The result showed: DSMs were round and smooth, and did not aggregate. The range of particle size distribution was narrow and 11.72%~24.58% were degraded after 8h. Quantity of linker had remarkable effect on degradability of DSMs. DSMs did not change in the airtight desiccator at room temperature. The stability test results that the storing stability of blank DSMs were pretty good. Methylene blue (MB) as model drug, drug loading of DSMs and the release of drug in DSMs were investigated. The result showed: the loading method and the quantity of added drug had greater effect on the quantity of loading drug and encapsulation efficiency. When the proportion of DSMs and drug was 20:1, the quantity of loading drug and encapsulation efficiency of incubation-absorption method was the smallest, and was 12.53gMB/gDSMs and 25.06%; entrapping method was 34.04 gMB/gDSMs and 68.08%; incubation-absorption method after the second cross linking reaction 37.15gMB/gDSMs and 74.29%. The greater the added drug, the greater the quantity of loading drug in three drug loading methods was, the smaller the encapsulation efficiency was. The loading method and the quantity of linker had greater effect on in-vitro release curve. Release curve of incubation-absorption and entrapping method had two phases—quick release phase and slow release phase. And the first phase lasted about one hour and released 70% drug. The release curve after the second cross linking reaction was steady, and cumulative percentage of release drug only arrived at 68.88%.It was elementary investigated That degradable starch microspheres(DSMs) adsorb peppermint oil. And builded the method that peppermint oil in DSMs was fastly measured. The result showed: Saturated adsorption quantity of DSMs was 84.74μL/g when the concentration of peppermint oil was 4% and adsorption time was 2h in the airtight container.