Prearation Of A Curcumin Controlled-Release Material By Atom Transfer Radical Polymerization

Curcumin has resistive effects on germs, oxidizers, HIV, tumors, etc. However, modern pharmacology has demonstrated that curcumin is readily degradable at alkaline conditions and easily decomposed under the light in organic solvents. Most of the orally administrated curcumin is destroyed by digestive juice in gastrointestinal tract and only very limited amount of curcumin could be absorded by body tissues via blood circulation due to the water-insolubility of curcumin. Currently, many efforts have been made to improve the water-solubility and bioavailability of curcumin in, but there are still many challenges that need to be resolved.1) It’s diffcult to control the curcumin release rate.2) The curcumin carrier has a poor dilution stability.3) It’s incapable to introduce targeting groups to curcumin carriers. Atom Transfer Radical Polymerization (ATRP) is a novel "living"/controlled radical polymerization technique and has been widely used to synthesize a large varity of block, graft, star and hyperbranched (co)polymers with defined structures, which make ATRP very promising for commercial applications at industrial scales.This work aims to synthesize the curcumin controlled-release materials by ATRP. The thesis mainly covers following aspects:1. A curcumin-based initiator (Br-Curcumin-Br) was synthesized by acylation reaction of curcumin with 2-bromoisobutyryl bromide and then the initiator was used to initiate the polymerization of methyl methacrylate (MMA) using CuBr/Bpy as a catalyst. The variation of monomer conversion and molecular weight with reaction time and the dependence of molecular weights on monomer conversions were investigated. The results showed that the monomer conversion increased with the increase of reaction time, and the polymer molecular weight increased linearly with monomer conversion. The obtained polymers had a relative narrow molecular weight distribution.2. An amphiphilic polymer, (PEG)-curcumin-(PEG), was synthesized by ATRP of poly (ethylene glycol) methyl ether acrylate with Br-curcumin-Br as an initiator. The molecular weight and composition of the polymer were examined by gel permeation chromatograph (GPC).3. The (PEG)-b-(Si)-Curcumin-(Si)-b-(PEG) amphiphilic block copolymer was synthesized by successive ATRP of 3-(trimethoxysilyl) propyl methacrylate and poly (ethylene glycol) methyl ether acrylate with Br-curcumin-Br as an initiator. The molecular weight and composition of the copolymer were examined by GPC and nuclear magnetic resonance spectroscopy (NMR), etc.4. The curcumin controlled-release nanoparticles were formed from amphiphilic polymers (PEG)-curcumin-(PEG) and amphiphilic block copolymers (PEG)-b-(Si)-curcumin-(Si)-b-(PEG) by dispension of the polymers in water. The size and the Zeta potential of the nanoparticles were subsequently measured and the results showed that the nanoparticles formed from (PEG)-b-(Si)-Curcumin-(Si)-b-(PEG) had a uniform size distribution and very good stability under various experimental conditions.