Synthesis And Characterization Of Functional Poly (s-caprolactone) Amphiphilic Polymer

Hydrophobic aliphatic polyesters such as poly(L-lactide)(PLA), polyglycolide(PGA) and poly(-caprolactone)(PCL) are of great important synthetic biomaterialsfor biomedical applications. These materials possess exceptional biocompatibility;biodegradability; low immunogenicity and good mechanical properties whichfacilitated their value as components of surgical suture, skeleton fixation, tissueengneering and drug delivery systems. Among these, PCL especially has been widelyexplored due to its good compatibility and neutral degradation end products which donot alter the pH of the degradation medium. However, the biodegradation rates ofPCL is difficult to control due to its hydrophobicity and crystallinity. Therefore,preparation of modifying PCL is of great necessity.In the present study, pendent functional amphiphilic aliphatic polyester wasprepared from methoxy poly(ethylene glycol)(MPEG) and functional ε-caprolactonemonomer, which was obtained by ring-opening polymerization. The main contentswere as follows:1．Amphiphilic biodegradable diblock copolymer bearing aldehyde groups wassynthesized by the combination of ring-opening polymerization (ROP) andthio-bromo “click” chemistry. The free aldehyde groups on the copolymer werereacted with hydrophobic payloads (p-methoxylaniline as a model drug) viabenzoic-imine linker, which was responsive to pH change. In addition, we alsoinvestigated the model drug release profiles.1H NMR、FT-IR、GPC、UV-Vis、SFS、DLS and AFM were used to investigate.2．γ-(acetic acid tert-butyl ester)-ε-caprolactone monomer (γAABεCL) wassynthesized. Amphiphilic aliphatic polyesters, methoxy-poly(ethylene-glycol)-block-poly(γ-(acetic acid tert-butyl ester)-ε-caprolactone)(MPEG-block-P(γAABεCL)),were prepared by ring-opening polymerization using stannous(II)2-ethylhexanoate(Sn(Oct)2) as catalyst and mPEG as macroinitiator. These products were characterizedby1H NMR、13C NMR、FT-IR and GPC.3．Amphiphilic polymer (MPEG-block-P(γAABεCL)6) was treated with TFA toremove the protective carboxyl groups. After deprotection, the pendant carboxylgroups on the cyclic ester units were reacted with paclitaxel (PTX) to achievemPEG-block-P(γAAεCL/PTXL) conjugate prodrug.1H NMR、FT-IR、GPC、SFS、 DLS and AFM were employed to inverstigate these polymers.