Study On Drug Sustained-Release Of PCL/PEG Electrospinning Microtiber

In recent years, the rapid development of nano-materials technology, nano fiberwas the central issue of fiber-disciplinary research. As the most important techniqueto produce microfiber, the production process of electrospinning was simple andeconomical. The characteristics of microfiber had small of fiber number,interconnected pore structure and the higher specific surface area. Electrospinning hadbeen widely applied in the field of biomedical, such as tissue engineering scaffolds,drug delivery and controlled release, wound dressing and so on. The electrospun fiberdrug controlled release system was the newer dosagefield of drug release. Completionof electrospinning relied on electrostatic force, and it could add many conventionaldrugs or even protein molecules to the spinning solution. The polymer waselectrospun to achieve the loading of the drug, simultaneously. This way enabled thedrug to be uniformly dispersed into the polymer fibers, thus effectively avoiding thedegeneration and failure of the active ingredient. By changing the preparationconditions and adjusting the structure of the material, it could achieve the purpose ofcontrolling the amount of drug release and the rate of drug release.This thesis made biodegradable amphiphilic polymer---Polycaprolactone（PCL） and polyethylene glycol （PEG）, THF as solvent, PCL and PEG blend toimprove the hydrophily of PCL and biodegradability, and formed the stable PCL/PEG microfiber by electrospinning technology. The microfiber was observed themicrofiber morphology and diameter distribution by scanning electron microscopy（SEM）.The author systematically studied the influence of electrospinningparameters, the different proportions of blending and the addition of different amountson fiber’s morphology and structure. The results showed that the film-formingproperties were well by electrospinning; the fiber’s diameter was reduced with theconcentration of spinning solution decreasing, the proportion of the PEG in the blends,the content of florfenicol, voltage and electrode distance increasing. However, thecrystallization temperature of PCL and PEG was low, the microfiber arise the phenomenon of crystal growth. The compatibility and crystallization kinetics of PCL/PEG microfiber were analyzed by differential scanning calorimeter （DSC）. Theresults showed that when the PEG content of less than50%, the compatibility of theblends was well. Studying non-isothermal crystallization kinetics showed: thecrystallization mechanism of PCL was not changed in the PCL/PEG blends, but theaddition of PEG affect the rate of PCL crystallization. Simultaneously, DSC resultsindicated that the crystallization temperature of blends was higher than thecrystallization temperature of pure PCL. The PCL/PEG microfiber as the drug carrierand florfenicol as the model drug, the blend solution was electrospinning. The authorused UV-spectrophotometer to characterize the release of electrospunflorfenicol-PCL/PEG microfiber and studied them by means of in vitro release. Thestudying indicated that: the PCL/PEG microfiber does not interfere with themaximum absorption wavelength of florfenicol266nm, and PCL/PEG blends cangreatly improve the water-solubility of florfenicol, microfiber had obvious sustainedrelease pattern for florfenicol. Within50hours, the cumulative drug releasepercentage of drug florfenicol loaded PCL/PEG microfiber is from60to90percent.With the content of PEG and florfenicol increasing the rate of drug dissolutionbecomes faster.