Boustta Mahfoud, Vert Michel
Department of Artificial Biopolymer, Institute for Biomolecules Max Mousseron, UMR CNRS 5247, Faculty of Pharmacy, University of Montpellier-CNRS-ENSCM, 15 Avenue Charles Flahault, BP 14491, 34093 Montpellier CEDEX 5, France.
Gels. 2019 Mar 3;5(1):13. doi: 10.3390/gels5010013.
In the presence of water, poly(-acryloyl glycinamide) homopolymers form highly swollen hydrogels that undergo fast and reversible gel↔sol transitions on heating. According to the literature, the transition temperature depends on concentration and average molecular weight, and in the case of copolymers, composition and hydrophilic/hydrophobic character. In this article, we wish to introduce new copolymers made by free radical polymerization of mixtures of -acryloyl glycinamide and of its analog optically active -acryloyl l-alaninamide in various proportions. The -acryloyl l-alaninamide monomer was selected in attempts to introduce hydrophobicity and chirality in addition to thermo-responsiveness of the Upper Critical Solubilization Temperature-type. The characterization of the resulting copolymers included solubility in solvents, dynamic viscosity in solution, Fourrier Transform Infrared, Nuclear Magnetic Resonance, and Circular Dichroism spectra. Gel→sol transition temperatures were determined in phosphate buffer (pH = 7.4, isotonic to 320 mOsm/dm³). The release characteristics of hydrophilic Methylene Blue and hydrophobic Risperidone entrapped in poly(-acryloyl glycinamide) and in two copolymers containing 50 and 75% of alanine-based units, respectively, were compared. It was found that increasing the content in -acryloyl-alaninamide-based units increased the gel→sol transition temperature, decreased the gel consistency, and increased the release rate of Risperidone, but not that of Methylene Blue, with respect to homo poly(-acryloyl glycinamide). The increase observed in the case of Risperidone appeared to be related to the hydrophobicity generated by alanine residues.
在有水存在的情况下，聚（丙烯酰甘氨酰胺）均聚物会形成高度溶胀的水凝胶，这种水凝胶在加热时会发生快速且可逆的凝胶⇄溶胶转变。根据文献记载，转变温度取决于浓度和平均分子量，对于共聚物而言，还取决于组成以及亲水/疏水特性。在本文中，我们希望介绍通过自由基聚合由不同比例的丙烯酰甘氨酰胺及其类似物光学活性丙烯酰-L-丙氨酰胺混合物制成的新型共聚物。选择丙烯酰-L-丙氨酰胺单体是为了除了引入上临界溶解温度型的热响应性之外，还引入疏水性和手性。所得共聚物的表征包括在溶剂中的溶解度、溶液中的动态粘度、傅里叶变换红外光谱、核磁共振光谱和圆二色光谱。在磷酸盐缓冲液（pH = 7.4，等渗至320 mOsm/dm³）中测定凝胶→溶胶转变温度。比较了包裹在聚（丙烯酰甘氨酰胺）以及分别含有50%和75%丙氨酸基单元的两种共聚物中的亲水性亚甲蓝和疏水性利培酮的释放特性。结果发现，相对于聚（丙烯酰甘氨酰胺）均聚物，增加基于丙烯酰-丙氨酰胺单元的含量会提高凝胶→溶胶转变温度，降低凝胶稠度，并提高利培酮的释放速率，但不会提高亚甲蓝的释放速率。在利培酮的情况下观察到的增加似乎与丙氨酸残基产生的疏水性有关。
