Synthesis Of Polyanhydride And Application Research On Electrostatic Spinning

In recent years, biodegradable polymeric materials have been found to be useful in drug delivery, absorbable suture, surgical orthopedic device and cell tissue engineering applications. In these materials, polyanhydride was a kind of biodegradable polymer, which attracted the interest of many researchers, because it was biocompatible, surface-eroding behavior and the rate of degradation was adjustable. Up to now, many types of polyanhydrides have been synthesized, but in the controlled drug delivery systems, the most wide use of application is the copolymers which are synthesized by different monomer ratios. The main cause include two parts. On the one hand, with the increasing application of controlled drug delivery systems, polyanhydride homopolymer can not meet requirement for drug delivery. To adjust the rate of degradation only depend on molecular weight and molecular weight distribution of copolymers have limitation. On another hand, in order to improve impact strength, permeability and hydrophilicity, other polyanhydrides or biodegradable polymeric materials are incorporated into the polymer backbone, which improve the performance of polyanhydride to meet requirement for drug delivery. This paper also research in this respect, the main results are as follows:1. The biodegradable polyanhydride copolymers composed of p-carboxyhenoxy propane (CPP) and sebacic acid (SA) in different weight ratios were polymerized by a melt polycondensation process. Additionally, several factors which affected the molecular weight had been studied, such as reaction time, reaction temperature and so on. The optimized conditions under laboratory conditions were vacuum degree 55mmHg, reaction temperature 180℃and reaction time 2h. The copolymers were characterized by FT-IR, ¹H NMR, Ubbelohde viscometer, differential scanning calorimetry (DSC) and X-ray diffraction (XRD) etc. It show that all the prepared polyanhydrides possesses high molecular weights, low melting points, and desired thermal stability. It was found that PCPP chain segment exhibit more stable than PSA after being investigated by FTIR spectra between 24-300℃. The peaks of 1471, 1412, 1359 cm^-1 changed sharply after 70℃in this process. It was deduced that these three peaks are linked to the crystalline of P(CPP-SA).2. A series of biodegradable poly(ether-anhydrides) composed of poly(ethyleneglycol)(PEG), and 1,3-bis(carboxyphenoxy)propane(CPP), sebacic acid(SA), or PluronicF127 and sebacic acid(SA) were synthesized by a melt polycondensation process. Characterization of the copolymers by FTIR and ¹H NMR confirms their structures. The physical and chemical properties showed that all the prepared poly(ether-anhydrides) meet the essential requirement for polyanhydrides as drug delivery material including high molecular weights, low melting points, and desired thermal stability. Meanwhile, the research shows that PEG blocks existed has great influence on molecular weight, crystallinity and hydrophilicity of polyanhydride.3. Copolymer ultrafine fibers, which contain paracetamol as a model drug and P(CPP-SA) were prepared by electrostatic spinning. The experimental results showed that degradation rate was fast in the fist day and slowed in the following period, furthermore the degradation rate decreased with the increase of the content of CPP in copolymers. These results reveal the degradation is closely related to copolymer composition and geometry of matrice. In vitro release study showed that polyanhydride erosion is the mechanism of drug controlled release. There was an initial burst release about 45% and sustained released in the following period.