Monodisperse Microspheres As Drug Release System Prepared By Shirasu Porous Glass (SPG)

By employing Shirasu Porous Glass(SPG) emulsification technique,uniform polymer microspheres can be obtained.Disperse phase are permeated the holes through the SPG membrane by the press to form globelets and then rushed away by the continue phase.SPG emulsification is a simle and manageable technique.This way also has advantages such as lower wasted power,excellent homogenization and good stability and so on.So it can be used to prepare functional homogenized microspheres or microcapsules.Meanwhile,hard to manufacture nano-particles with diameter less than 1μm is the disadvantage.So we use the dialysis to prepare homogenized nano-particles carrying drug based on the former research of this laboratory.In this work,a simle,manageable and easy to apply in industrial production way to produce microcapsules & microspheres was developed by using SPG Further more, sustained release HCPT-loaded micrespheres possessing high loading capacity and encapsulation efficiency were prepared.The collagen membrane was tentatively prepared for an expectation of implantable preparation.The main contents and results of the thesis are outlined as follows:(1) Microparticles without HCPT prepared by SPG emulsification:Different conditions such as diameter of SPG holes,variety of emulsifier,Na pressure, temperature for volatilization,ratio of disperse phase and continue phase etc were studied on the results of preparation.The theory that different factors cause diverse result was discussed and the conditions and methods to control the particle size and distribution were affirmed.(2) Study on the process to form PLA micro-particles and the mechanism lead to size dispersed:By employing the SEM and Nano-zs,the figure change and size variety were observed to analysis the process to form particles.The result indicates that the different size especially the bigger ones were shaped by the droplets mergence.(3) Preparation of HCPT-loaded microspheres by SPG:the shape and size distribution were viewed and drug content and drug encapsulation were tested.The result shows that microspheres produced in this way have a character of spherical shape,homogeneous size distribution(between 1μm～10μm) and high drug content & drug encapsulation.HCPT-loaded nanoparticles were prepared by dialysis. Nanoparticles made in this way also had a homogeneous spherical shape while size distribution was between 300 nm～1μm.(4) The membrane loading with HCPT microspheres was prepared and investigated primarily.Membrane was gained by blending the microspheres and collagen.The drug release characterization indicates that collagen membrane can delay the drug release to a certain extent.