Fabrication And Drug Release Properties Of Drug-loaded PVA/CS Nanofiber System

The electrospinning technique as a novel method to fabricate drug delivery system had been paid a great attention due to its advantages of simple and easily operated,fabricated fiber with high drug loading.In addition,chitosan(CS)and poly(vinyl alcohol)(PVA)had been widely used due to its excellent biocompatibility and biodegradability.Therefore,the PVA/CS fiber wrapped with ampicillin sodium was applied as the drug delivery system,and the morphology,properties and drug release of composite fiber were adjusted by controlling material formulation,processing,crosslinking conditions in this dissertation.The main works are as follows:1.PVA/CS composite fibers were fabricated by electrospinning in this study.The influences of material formulation and formed time on the viscosity,electrical conductivity and the morphology,average diameter,diameter distribution of PVA/CS composite fiber were investigated.The results showed that,the introduction of CS could increase the viscosity,electrical conductivity of PVA/CS blend solution.And the viscosity of blend solution decreased with the increasing of formed time.In addition,the more CS content was,the smaller diameter of CS/PVA composite fiber would be.The fiber-forming capacity of PVA/CS blend solution decreases dramatically as the solution formed time increases.2.The crosslinking modification of PVA/CS composite fiber were prepared by using glutaraldehyde and hydrochloric acid as cross linking agent and catalyst,respectively.The influence of material formulation,cross linking agent concentration and catalyst concentration on the morphology,thermal and mechanical property,degrees cross linking and hydrophilic properties of PVA/CS composite fiber were studied.The results showed that the PVA/CS composite fiber was successfully crossed linking,and showed the fine morphology.The Young's modulus and tensile stress increased,the elongation at break decreased with the increasing of catalyst concentration.The hydrophobicity of crossed linking PVA/CS composite fiber was significant improved compared with PVA/CS fiber,which could help to decrease the rate of drug release.3.PVA/CS/ampicillin sodium composite fibers were fabricated by electrospinning and were modified by crosslinking.The influence of material formulation,cross linking agent concentration and drug loaded on the morphology,drug release and encapsulation of drug-loaded PVA/CS composite fiber were studied.The results showed that the PVA/CS/ampicillin sodium composite fiber was successfully crossed linking,and showed the fine morphology.The drug release and encapsulation of drug-loaded PVA/CS composite fiber decreased with the increasing of cross linking agent concentration.The drug release increased and drug encapsulation decreased with the increasing of CS content.It included that the aim of decreasing drug release could be achieved by improving the crosslinking degree and decreasing CS content.