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Synthesis of Amphiphilic Biodegradable Block Copolymers and Their Use as Drug Carriers

Author: XuBo
Tutor: GaoQingYu
School: Henan University
Course: Polymer Chemistry and Physics
Keywords: Biodegradable Amphiphilic block copolymers Polymeric micelles Preparation Controlled drug release
CLC: R944
Type: Master's thesis
Year: 2009
Downloads: 328
Quote: 1
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Abstract

Currently, biodegradable polymeric carrier material has become a hot topic. A pharmaceutical preparation with a biodegradable material is degraded into small molecule compounds after metabolism in the human body, to avoid carrier material accumulate in the body, while the rate of drug release can be controlled by the degradation rate of the material. In this work, we have prepared a series of amphiphilic biodegradable polymer, characterized by their structure, to study the behavior of the drug-loaded micelles under different conditions in vitro release of folic acid. First, we use a method of ring-opening polymerization, and a functional group coupling synthesized cysteine ??modified amphiphilic biodegradable block copolymer of poly-lactic acid-b-polyethylene glycol - cysteine ??(APLA-b- PEG-Cys). FTIR, 1 ~ H-NMR to characterize its structure, GPC determined molecular weight and molecular weight distribution. Amphiphilic block copolymers APLA-b-PEG-Cys in the aqueous phase self-assemble into polymeric micelles, the fluorescent probe Determination of the critical micelle concentration CMC of the polymer. In order to enhance the stability of the polymeric micelles to control the release behavior of the model drug folate, we use the in situ condensation reaction of the amino group and a carboxyl group of the micelle surface, the shell cross-linking has occurred the polymer micelle APLA-b-PEG-Cys . And to study the impact of the shell crosslinking on the physical and chemical properties of the micelles, and found shell crosslinking reduces the micellar surface charge, reducing the particle size of micelles, slowing the rate of drug release. This biodegradable amphiphilic polymer may be used in drug delivery systems. Second, the synthesis of a series of different block ratio amphiphilic triblock copolymer, and investigated under different conditions, the control and release of folic acid. Bis hydroxy polyethylene glycol (DHPEG) as initiator and stannous octoate catalyzed initiator ε-cyclohexyl lactone (ε-CL) open ring polymerization, synthesis of poly (caprolactone)-b-polyethylene glycol - b-polycaprolactone amphiphilic triblock copolymer (PCL-b-PEG-b-PCL, PCEC), FTIR, 1 ~ H-NMR and GPC characterization methods to determine of PCEC the composition and structure; nano-micelles with a core / shell structure prepared by membrane dialysis; the fluorescent probe Determination of polymer micelles critical micelle concentration CMC and CMC value increases as the polymer hydrophobic PCL block length decrease; the polymeric micelles TEM figure shows the DLS results show micellar particle size distribution is very narrow, and the particle size increases with increasing PCL block length; folic acid as a model drug, and its morphology is spherical, found micelle particle size, drug loading, drug release behavior influenced by feeding FA / PCEC ratio. Polymer PCEC micelles folic acid can delay the release in vitro, and drug release behavior is also influenced by the release medium pH.

Synthesis of Amphiphilic Biodegradable Block Copolymers and Their Use as Drug Carriers

Abstract

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