| In recent years, with the rapid development of modern science and technology, current status of study on the pharmaceutical preparations has transferred from simple traditional formulation to drug delivery systems. Oral administration is the most commonly used traditional administration way, in which oral controlled release drug delivery system is attracted much attention by virtue of its high medication safety and bioavailability. To the pharmaceutical industry, the research and development of the new drug carrier and effective delivery system has become an urgent task. Therefore, developing suitable starch-based aqueous oral controlled release drug carrier coating materials not only meet the modern trend of drug release systems but also expand the application of starch in the field of medicine, which is of great theoretical significance and economic value.According to the requirements of the aqueous film coating materials preparation and characteristics of coating process, through the system research of the rheological properties, retrogradation stability and film properties of gelatinized high-amylose maize starch, established the aqueous starch based coating fluid system. Used light microscopy, gel chromatography-static and dynamic laser light scattering, X-ray diffraction, small angle X-ray scattering, infrared spectrum, In vitro digestion test and other modern analytical techniques, studied the physical reorganization of starch which was heated through swelling, pasting, regathering, drying and other film-forming process, the changes in its structure and coating properties which affected the drug release properties, optimized the preparation conditions and the performance of resistance to digestion of the starch-based aqueous oral drug carrier coating materials. Gelatinized the starch at 120oC under 1500 psi pressure for 60 min when the concentration was 30%, the anti-digestion property of starch could reach to 39.90%.On this basis, drug-loaded pellets were prepared by extrusion spheronization, with 5-amino salicylic acid as model drug. Coated the drug-loaded pellets with high amylose maize starch. By adjusting the conditions of gelatinization and coating film-forming, the effects of plasticizer content, coating thickness and anti-digestibility of starch to the releasing performance of starch based coated drug pellets in gastrointestinal environments were investigated, optimized the preparation process of starch based coated pellets, and build the corresponding oral starch-based coated pellets of gastrointestinal drug delivery system. The results showed that the drug release properties of starch aqueous film coated pellets was affected by the anti-digestion of the coating liquid, through the regulation of anti-digestive performance of coating liquid, to control the release properties of the coated drug pellets. The higher the anti-digestive performance of the coating liquid is, the higher the control release capability of the coated pellets are, drug released gentle. Improved the anti-digestion capability of the coating liquid to a certain degree, can make the coated pellets release drug slowly.In this thesis, used natural polysaccharides-the high amylose maize starch as research subjects which is rich in the natural and has good biocompatibility, appropriated physical modification techniques, reasonable regulated the relationship of starch molecules between structure and anti-digest properties in the coating process by physical restructuring, obtained starch based oral control release drug carrier material which is suitable for aqueous coating, established a starch-based coated pellets oral drug delivery system. The results established the basis of high-amylose maize starch working as the aqueous liquid control releasing coating material which is fulfilled the releasing capability in the digestive tract, provided a new way of thinking for starch processing and the development of renewable resources. |
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