Synthesis of Dextran/Methoxy Poly(ethylene glycol) Block Copolymer

Abstract

We synthesized a block copolymer composed of dextran and methoxy poly(ethylene glycol) (mPEG). To accomplish this, the end group of dextran was modified by reductive amination. The aminated dextran (Dextran-NH2) showed the intrinsic peaks of both dextran at 3~5.5 ppm and hexamethylene diamine at 1~2.6 ppm at1H nuclear magnetic resonance (NMR) spectrum. The amino end group of dextran was conjugated with mPEG to make the block copolymer consisting of dextran/mPEG (abbreviated as DexPEG). The synthesized aminated dextran and DexPEG were characterized using1H NMR and gel permeation chromatography (GPC). The molecular weight and conjugation yield were estimated by comparing the intensity ratio of the proton peaks of the glucose molecule (4.9 ppm and 3.3~4.0 ppm) to that of the ethylene group of mPEG (3.7 ppm). Abundant hydroxyl group in the dextran chain can be used as a source of bioactive agent conjugation.

Terpene and Dextran Renewable Resources for the Synthesis of Amphiphilic Biopolymers

“…We should note that the absence of dextran degradation during reductive amination has been previously shown by the analysis of the molar mass of dextran before and after the reaction. 38 The hydrophilic lipophilic balance…”

“…A functionalization degree of 94% proved the success of the reductive amination reaction. We should note that the absence of dextran degradation during reductive amination has been previously shown by the analysis of the molar mass of dextran before and after the reaction . The hydrophilic lipophilic balance (HLB) of the end-modified dextran polymer (Dext-DHM) was calculated from the simplified Griffin method proposed for nonionic surfactants (HLB = 20 × (molar mass hydrophilic moiety/molar mass hydrophobic moiety)) .…”

“…We should note that the absence of dextran degradation during reductive amination has been previously shown by the analysis of the molar mass of dextran before and after the reaction. 38 The hydrophilic lipophilic balance (HLB) of the end-modified dextran polymer (Dext-DHM) was calculated from the simplified Griffin method proposed for nonionic surfactants (HLB = 20 × (molar mass hydrophilic moiety/molar mass hydrophobic moiety)). 39 The calculated HLB value of the synthesized Dext-DHM (HLB ∼ 18.5) is close to Tween 20 nonionic surfactants (poly(ethylene oxide) sorbitan fatty acid esters with lauric acid hydrophobic group and 20 ethylene oxide units), 40 which are known for their wide range of emulsifying properties.…”