Koyama Y, Umehara M, Mizuno A, Itaba M, Yasukouchi T, Natsume K, Suginaka A
Department of Home Economics, Otsuma Women's University, Tokyo, Japan.
Bioconjug Chem. 1996 May-Jun;7(3):298-301. doi: 10.1021/bc9600123.
Novel poly(ethylene glycol) (PEG) derivatives having pendant amino groups were prepared by copolymerization of allyl glycidyl ether with ethylene oxide followed by chemical modification of the double bond side chains. Dropwise addition of the mixture of monomers to the anionic initiator gave an almost monodisperse (Mw/Mn = 1.05) random copolymer. 1H NMR spectra showed that addition of 2-aminoethanethiol to the pendant allyl groups of the copolymer was completely carried out in methanol without catalyst, and an aminated PEG derivative with a definite structure was obtained. Acetylation of the pendant amino groups was readily performed by acetic anhydride with triethylamine. A gel permeation chromatogram of the acetylated polymer showed a very narrow molecular weight distribution (Mw/Mn = 1.06) of the polyamine. These cationic PEG derivatives make amphiphilic polyion complexes with fatty acids, and then aggregate in water. A fluorescence study using pyrene as a microenvironment probe revealed that the aminated PEG-lauric acid ion complex could take up the hydrophobic fluorescence probe into the lipophilic field inside, and they also had a critical aggregation concentration at [lauric acid] = 0.7 mM. It is much lower than the critical micelle concentration of the corresponding fatty acid sodium salts, indicating high stability of the polymer-fatty acid aggregate.
通过烯丙基缩水甘油醚与环氧乙烷共聚，随后对双键侧链进行化学改性，制备了具有侧链氨基的新型聚乙二醇（PEG）衍生物。将单体混合物滴加到阴离子引发剂中，得到了几乎单分散（Mw/Mn = 1.05）的无规共聚物。1H NMR光谱表明，在无催化剂的情况下，2-氨基乙硫醇与共聚物的侧链烯丙基的加成反应在甲醇中完全进行，从而得到了具有确定结构的胺化PEG衍生物。侧链氨基的乙酰化反应可通过乙酸酐与三乙胺轻松完成。乙酰化聚合物的凝胶渗透色谱图显示多胺的分子量分布非常窄（Mw/Mn = 1.06）。这些阳离子PEG衍生物与脂肪酸形成两亲性聚离子复合物，然后在水中聚集。使用芘作为微环境探针的荧光研究表明，胺化PEG-月桂酸离子复合物可将疏水性荧光探针吸收到内部的亲脂区域，并且它们在[月桂酸]= 0.7 mM时也有临界聚集浓度。它远低于相应脂肪酸钠盐的临界胶束浓度，表明聚合物-脂肪酸聚集体具有高稳定性。
