The Combination And Function Research Of The Drug-Eluting Stents Coated With Azithromycin Nano-Particles

With the wide application of stent implantation in vivo, the problem of restenosis(ISR) caused by stent implantation has been paid more and more attention. In recent years, focusing on the variety mechanism of ISR, a lot of different drug-eluting stents have been developed. The stents are coated with a kind of polymer with which to combine with therapeutic drugs. After the drug-eluting stents implanted into blood vessels, the drug can release slowly, and get function by the different mechanism, thus to achieve the treating and preventing purposes. The quality of the nano-particles coated stents directly determines their usage. The study of the article was mainly on the new method of using biodegradable polyester to coat azithromycin.About specific aspects of work carried out:(1),Using DMF as solvent to dissolve the biodegradable polycaprolactone and configure different concentrations of PCL solution. Selecting different molecular weight of PCL to configure solution with different drug-loading, and then stir it in the formation of a special instrument loaded azithromycin nano-particles.(2), Pushing the above solution (azithromycin-PCL-DMF) into deionized water and another deionized water which containes the surfactant Setting other contrast experiments by changing the external conditions to control the size of azithromycin and the shape of nano-particles.(3), Using dynamic light scattering and fluorescence spectroscopy test the Azithromycin-PCL formation mechanism in nano-size to study the relationship between size and different experimental condition. Prepare azithromycin nano-particles under different conditions and different potential zeta changes.(4),Prepare the Azithromycin-PCL nano-spheres in different polymerization conditions, which including temperature, the molecular weight of PCL, PCL concentration, the amount of azithromycin, the reaction medium pH, surfactant in deionized water concentration, stirring speed. It indicate that azithromycin is 40% compared with poly-caprolactone; the PCL molecular weight is 60,000; the PCL concentration is 10mg/ml, pH is 4.47, the temperature is 30℃, smaller particle size can be achieved with smooth, high drug loading Azithromycin-PCL-NP nano-particles.(5),Study the stability of Azithromycin-PCL nano-particles. Then research on its appearance shows how the temperature changes the nano-spheres size and surface morphology. With the increase of temperature, a slight decrease was occurred in microsphere size.(6),Using SEM, AFM to observe the surface morphology of microspheres Azithromycin-PCL nano-particles was smooth and rounded, and no obvious defects observed by TEM.(7),UV-Vis spectrophotometer tests azithromycin drug content.