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Environmental stimuli-responsive polymer materials identification and response to stimulation of the external environment (such as changes in pH, temperature, light, magnetic) shows a good prospect, and thus in many areas. More previous studies with environmental stimuli-responsive polymer, mostly non-biodegradable polymer compound, such as poly (N-isopropyl acrylamide), polyacrylic acid, poly-4 - vinyl pyridine, etc., as a biomedical material in vivo use will be subject to many restrictions. If the environmental stimuli-responsive, biodegradability, biocompatibility give a polymer, it can be suitable for in vivo applications, a new polymer material. The microspheres, formed by such materials may be used as the polymer carrier of the pharmaceutical preparation having a positioning release function. In this thesis, the N-methyl-threonine with lactic acid as monomer, the melt polycondensation method to obtain a series of a random copolymer having a pH sensitive. NMR spectrum analysis showed: the molecular chain of the copolymer containing the PLA, PDMT unit. By gel permeation chromatography (GPC), NMR ( 1 H-NMR) and infrared spectroscopy (FT-IR) polymer characterization; nano particle size analyzer measured at different pH values polymer particle size and potential, to prove its pH sensitivity. H 2 O 2 -Ac oxidation chitosan, a series of low molecular weight chitosan, using infrared spectroscopy and its N-alkyl modification (FT-IR) were used to characterize the modified chitosan, ultraviolet spectroscopy (UV) transmittance measured at different pH. The Fe with improved chemical coprecipitation prepared Fe 3 O 4 magnetic nanoparticles, chemically modified KH-570, stable dispersion was prepared 3 O 4 magnetic nanoparticles. By vibrating sample magnetometer (VSM), X-ray diffraction (XRD), infrared spectroscopy (FT-IR) of Fe 3 O 4 and modified Fe 3 O 4 magnetic nanoparticles were characterized using emulsion evaporation method wrapped magnetic N-alkylation of the anti-tumor specific drug etoposide modified chitosan microspheres ball. Vibrating sample magnetometer meter (VSM), X-ray diffractometer (XRD), scanning electron microscopy (SEM), thermal gravimetric analysis (TG) of magnetic polymer drug microspheres were characterized. Phosphate buffer solution (PBS, pH values ??were 5.5,7.4,11.5) system to examine the in vitro release of modified chitosan microspheres wrapped etoposide magnetic N-alkylation, UV-visible spectrophotometer ( UV) detection medium drug release behavior indicates that: the drug release process is composed of two phases, i.e. the initial drug burst release phase and the subsequent stable release phase.
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