Dissertation > Excellent graduate degree dissertation topics show

Drug Carriers Based on Complex Micelles Self-Assembled from Block Copolymers

Author: LiuXiaoJun
Tutor: ShiLinQi
School: Nankai University
Course: Polymer Chemistry and Physics
Keywords: block copolymer complex micelles charged channels glucose-responsive controlled release
CLC: TQ460
Type: PhD thesis
Year: 2012
Downloads: 33
Quote: 0
Read: Download Dissertation

Abstract


Polymeric micelles self-assembled from block copolymers have receivedenormous interest due to their capability to increase the solubility of insoluble drugsas well as their specific core-shell structure and good stability under physiologicalconditions. Micelles with core-shell-corona three-layered structure have beendemonstrated superior functions compared to their simple core-shell counterparts. Akey advantage of core-shell-corona micelles is that channels can be created in theshell, which could be applied in controlled drug release and other aspects. Moreover,the collapsed shell could not only restrain burst drug release but also controldegradation of the micelle core. Release behavior of ionic drugs from simplemicelles is obviously pH-sensitive. Polymeric complex micelles with chargedchannels on the surface provided us with an effective way to reduce the difference inthe drug release rate upon change of pH value. In addition, complex micelles withglucose-responsive shell were prepared. Repeated self-regulation of GCM releasefrom the micelles was achieved based on reversible collapse and stretch of the shellresponding to external glucose concentration.The block copolymer PCL-b-PAsp was synthesized by sequential ROP ofε-caprolactone and Asp (OBzl)-NCA. The block copolymer PCL-b-PNIPAM wassynthesized by ROP and ATRP. At room temperature, diblock copolymers ofPCL-b-PNIPAM and PCL-b-PAsp self-assembled into complex micelles with a PCLcore and a mixed PAsp/PNIPAM shell. By increasing the temperature, these complexmicelles could be converted into a core-shell-corona structure composed of a PCLcore, a collapsed PNIPAM shell and a soluble PAsp corona, and the PAsp chainsstretched from the inner core to outside, leading to the formation of charged PAspchannels. PAsp could ionize and its ionization degree and conformation could varywith pH values in aqueous solution. pH dependent release behavior of ionic drugswas effectively reduced through the interaction between charges and the variation ofconfiguration of PAsp chains. The PAsp segments of PCL-b-PAsp was modified by3-aminophenylboronic acid(APBA) to obtain the polymer PCL-b-P(Asp-co-AspPBA). PCL-b-PEG wassynthesized by ring opening polymerization (ROP) of ε-caprolactone using PEG-OHas the initiator. In alkaline water, PCL-b-PEG and PCL-b-P(Asp-co-AspPBA)self-assembled into complex micelles with a PCL core and a mixed PEG/P(Asp-co-AspPBA) shell. After dialysis against acidic water, these complex micellescould be converted into a core-shell-corona structure composed of a PCL core, acollapsed P(Asp-co-AspPBA) shell and a soluble PEG corona, and the PEG chainsstretched from the inner core to outside, leading to the formation of PEG channels.Under high glucose concentration at pH7.4, the hydrophobic P(Asp-co-AspPBA)chains would become hydrophilic gradually, leading to disaggregation of thecollapsed shell and rapid drug release rate. When glucose concentration decreased tovery low level, the P(Asp-co-AspPBA) chains would reversibly collapse onto thePCL core. The formation of collapsed shell could effectively decrease the drugrelease rate. Based on reversible collapse and stretch of P(Asp-co-AspPBA) chainsresponding to external glucose concentration, repeated self-regulation of GCMrelease from the micelles was achieved.

Related Dissertations

  1. Study on the Effect of Sea Brine Controlled Release Nitrogenous Fertilizer with Oyster Shells as the Carrier on the Grown Activites of Coriander and Cayenne Pepper,S145.6
  2. Effects of Controlled-Release Compound Fertilizeron the Physiological Properties, Growth Development As Well As Quality of Flue-Cured Tobacco,S572
  3. Synthesis of Silica Particles Grafted with Well-defined Complex Macromolecular Architectures,O634.41
  4. The Research on the Preparation of Temperature/pH-sensitive Copolymer Materials and the Release Behavior of Its Load Paclitaxel,O631.3
  5. Synthesis of DMAEMA/ BMA Block Copolymer,O631.3
  6. Synthesis of Functional Block Copolymer of Polyphosphoester and Their Functionlization,O631.3
  7. Hydrophilic silicone softener Development and Application,TS195.23
  8. Synthesis of block polymers and their composites with CNTs,TB332
  9. Self-assembly Behavior of Tussah Silk Fibroin and Application in Drug Controlled Release,R318.08
  10. Design, Preparation and Perfermance Study of Controlled Release Systems Based on Mesoporous Silica Nanoparticles(MSNs) and one Sensor for Lithium Ions,TP212
  11. Preparation,characterization of Urokinase-loaded Chitosan Nanoparticles and in Vitro Simulation of Thrombolytic Test,TQ460.1
  12. Effects of Continuous Non-flooded Plastic Film Mulching Cultivation and Applying Controlled-release Coated Urea on Rice Growth and Soil Fertility,S511
  13. Effects of Controlled-release Fertilizer on Rice Grain Yield and Nitrogen Loss in Paddy Fields,S511
  14. Application of Mesoporous Silica Nanoparticles on Drug Delivery,TB383.1
  15. Multi-block type sulfonated poly ether sulfone proton exchange membrane preparation and properties of,TM911.4
  16. Preparation of Feather Keratin Compound Film and Its Applications,X713
  17. The Interactions between Protein and Hydrophobic Modified Poly (Allylamine)s,O631.3
  18. Preparation of Betahistine Mesilate Controlled Porosity Osmotic Pump Tablets and Study on Quality Standard,R94
  19. Research of the Amphiphilic Photosensitive Copolymer Self-assembly and Its Emulsification Properties,O631.3
  20. Micro/nanoparticles with Core-shell Structures for Programmable Controlled Release of Multiple Drugs,TQ460.1
  21. Study on Synthesis of Fluorine-containing Acrylate Block Copolymer by Atom Transfer Radical Polymerization,O631.3

CLC: > Industrial Technology > Chemical Industry > Pharmaceutical chemical industry > General issues
© 2012 www.DissertationTopic.Net  Mobile