The Preparation, Characterization And Properties Research Of The Controlled Release Microspheres

In the past of years, the standard of living is improved enormously, because of this, it is necessary to develop a new kind of drug delivery system, which can decrease the side-effect, improve the drug efficiency, prevent doing harm to human's body. In this paper, three kinds of promising microspheres were researched:1. Magnetic drug-loading microspheresMagnetic drug-loading microspheres consist of magnetic nanoparticles, which confers the drug carrier the property of magnetic responsiveness, and polymer carrier, which binds the intended anti-cancer drug. Such carriers are supposed to be targeted to the site of tumor by the applied magnetic field, and thus to achieve high local drug concentrations and reduce undesirable toxic side effects. This is a new way for the drug targeting. In this paper, the PEG-incorporated drug-loading microspheres and PEG un-incorporated drug-loading microspheres were all prepared by emulsion/heat-solidify method. The mean diameter, surface morphology, drug-loading, magnetic responsivity, in vitro release, in vivo distribution were all researched and compared. The results showed that the macroscopical characterization of the two kinds of microspheres was almost the same, but the PEG-incorporated drug-loading microspheres had better ability to delivery the anti-cancer drug to the targeted site.2. Biodegradable copolymer microspheresThe biodegradable copolymer (PCEC) was synthesized by ring-opening polymerization method and the structure was characterized. The microspheres were prepared using this copolymer and the size of the microspheres can be controlled. These microspheres were used to load the protein-drug. Beside this, the effect on the volume of inner aqueous phase, organic phase, nominal drug loading were researched in detail. The result showed that: the method we choiced was mild and the protein was keeping active. The drug released when the copolymer basis degraded, so there had a good controlled release capability.3. pH-sensitive microgelsIn recent years, considerable research attention has been focused on the environment-sensitive microgels because they possess great potential applications in many aspects, including drug delivery system, enzyme immobilization and biomaterials separation and purification, etc. Among them, pH responsive microgels have attracted great interest from both fundamental and application field at present. In this paper, the inverse suspension polymerization method was used to prepare the microgels. And the size, morphology, in vitro release, effect on the monomers were all researched. The results showed that: the microgels were about 15um, homogeneous and had good pH sensitivity.