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Poly (L-lacitde)/Poly (1,5-dioxepan-2-one) Blends in Drug Release Device

Poly (L-lacitde)/Poly (1,5-dioxepan-2-one) Blends in Drug Release Device. Maggie Wang October 27, 2000 The main article came from Journal of Polymer Science V38,786,2000. CONTENT. Introduction Gene Therapy Drug Delivery Immunoisolation Device Biodegradable Polyester

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Poly (L-lacitde)/Poly (1,5-dioxepan-2-one) Blends in Drug Release Device

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  1. Poly (L-lacitde)/Poly (1,5-dioxepan-2-one) Blends in Drug Release Device Maggie Wang October 27, 2000 The main article came from Journal of Polymer Science V38,786,2000

  2. CONTENT • Introduction Gene Therapy Drug Delivery Immunoisolation Device Biodegradable Polyester • Materials PLLA, PDXO, Copolymer, Homopolymer Blends • Result Analysis Microshpere Morphology, In vitro degradation, Drug Release, Storage Stability • Conclusion

  3. INTRODUCTION • Gene Therapy Human gene therapy is defined as a medical intervention based on the alteration of genetic material of living cells in humans. • Drug Delivery What’s the big challenge? two approaches • Cell Encapsulation---T.M.S. Chang 1964 What kind of requirement for the device? • Biodegradable Polyester

  4. MATERIALS CHARACTERISTIC Biodegradable Polyester • biocompatibility • nontoxicity • processability • resorption of degradation product

  5. Biodegradable Polyester The family Lactide, glycolide, -caprolcatone, trimethylene carbonate, etc Why did they need morphology engineering? • Hydrophobicity and semicrystalline • hard to control degradation rate • attachment to drug or protein

  6. PLLA- Poly (L-lactide) Bu2SnO 15h 120°C • Semicrystalline • Tg 55C • In Homopolymer, the crystalline domain show high resistance to degradation

  7. PDXO-Poly (1,5-dioxepan-2-one) Bu2SnO 14h 40°C • Completely amorphous • high viscous, Tg -39C • no tendency to crystallize, excellent choice for the amorphous block in a copolymer

  8. Copolymer P(L-LA-co-DXO) • Copolymer is semicrystalline • more flexible, moldable • consisting soft and hard segments: soft phase(DXO) elasticity and the degradation hard phase(LLA) mechanical strength

  9. Homopolymerization Blends PLLA-PDXO • Blends exhibit advantageous physical and mechanical properties • phase-separated can obtain double -layered particles • the degradation and release performance can be controlled by means of component ratio.

  10. RESULT ANALYSIS • Morphology of Microspheres • In vitro Degradation • Drug Release • Storage Stability

  11. Morphology of Microspheres Copolymer 50m Blends 20m Very porous interconnecting channels More dense less porous

  12. Crystallinity • crystallinity increase as the PLLA ratio increased • PDXO in the PLLA domains disturb the crystal

  13. DSC thermograms

  14. In vitro degradation • In theory,DXO are slower degrading than the L-LA • a high content of L-LA degrade faster • Copolymer trendency • Blends trendency---L-LA matrices resistant to water penetration

  15. Drug Release in buffer solution

  16. Storage Stability • Weight change ---moisture adsorption cause chain cleavage • higher humidity, more decrease of MW • storage induce crystallization • copolymer appear more sensitive to storage degradation

  17. CONLUSION

  18. Blends of PLLA-PDXOeasily control get what you want

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