Preparation And Study Of Drug-loaded Nano Particles And Multi-layered Nano Fibers And Their In Vitro Release

Drug delivery system refers to a kind of system providing different ways in clinical treatment. New forms of drug have sprung up with the rapid development of science and technology. Releasing drug through drug carriers has appealed to many researchers during the past decades. Size of a drug and its release rate affect its absorption in human body. Thus, a new kind of system with adjustable size, flexible preparations seems like a must. The electrospinning technology, therefore, assist the rise of this novel drug delivery system.This thesis made drug-loaded nano-particles and nano-fiber meshes using electrospraying and electrospinning, respectively. Then we characterized the resultant particles and fiber meshes so to investigate the influence that different preparations and drug earriers have on the morphology of the very particles and fiber meshes. In vitro release experiments were launched to study the regulating effect of distinct drug carriers.Drug-loaded nano-particles were prepared using electrospraying. SEM showed KET has a plump outlook while EC possesses hollow and irregular surface. It was noticed that as the amount of EC increased, the granules collapsed correspondingly and fiber diameters decreased. From the DSC and XRD studies, it was concluded that the crystalline drug was converted into the amorphous state in all the micro-particles. FTIR results indicated there was chemical interaction between the drug and polymer. From the dissolution studies, it was noted that as the amount of polymer increased, the drug release rate was gradually reduced. All these results showed that sustained drug delivery was realized using electrospraying.Studies on the EC viscosity, different preparations resulting distinct morphological features and in vitro drug release behaviors of nano-particles and nano-fiber meshes were made. SEM showed drug-loaded EC particles exhibited hollow and irregular surfaces and they were tightly linked while drug-loaded EC fiber meshes had uniform surface without beads indicating good compatibility between the drug and polymer. From the XRD results, it was found that the drug is dispersed at the molecular level in both matrixes. In vitro experiment revealed that drug released from both matrixes experience the same fast-to-slow release stages. Drug-loaded EC fiber meshes, however, released more drug with faster speed than EC particles within the same period, thus, the former realized a relatively good sustained release behaviors.Mono-layered drug-loaded fiber meshes were prepared applying different polymers with different content. This thesis described KET-PVP meshes and KET-EC meshes. SEM revealed that meshes have the most agreeable morphological features when drug to polymer ratio is1to4. XRD results showed that the crystalline drug was converted into the amorphous state in both kinds of meshes. From the in vitro release experiment, it could be conclude that PVP could accelerate the drug release rate while EC assist a sustained release. Drug release behavior related to fiber diameter which could be regulated by polymer content in the spinning solution-higher polymer content leaded to fatter fibers extending the sustained release period. In conclusion, electro spinning is an easy method in regulating drug release rate through flexibly adjusting fiber diameter.Tri-layered drug-loaded meshes were prepared using electrospinning achieving biphasic release. The first and the third layer were fabricated using PVP while the second layer was made using EC. This kind of novel device was designed to relieve pain instantly at first and then prolong analgesia followed by strenghtened drug release to consolidate curative effect at last. SEM showed that meshes thickness increased when extending the spinning time. In vitro release experiment revealed that drug release behavior was affected by mesh thickness-more drug released with faster speed as increasing PVP content in the first layer. In conclusion, duration of drug release could be controlled by mesh thickness using electrospinning.