Akala E O, Kopecková P, Kopecek J
Department of Pharmaceutics and Pharmaceutical Chemistry/CCCD, University of Utah, Salt Lake City 84112, USA.
Biomaterials. 1998 Jun;19(11-12):1037-47. doi: 10.1016/s0142-9612(98)00023-4.
Novel pH-sensitive hydrogels were synthesized by copolymerization of N,N-dimethylacrylamide, tert.-butylacrylamide, acrylic acid, 4,4'-di(methacryloylamino)azobenzene, and N-alkanoyl, O-methacryloylhydroxylamines. The influence of the length (and consequently hydrophobicity) of the alkanoyl (propionyl, hexanoyl, and lauroyl), and its content in the hydrogel on the kinetics of swelling were investigated. Upon change in the pH from acidic to neutral, N-alkanoyl, O-acylhydroxylamine moieties were hydrolyzed. The rate of side-chain hydrolysis was dependent on the length of the alkyl and the content of the hydrolyzable comonomer in the network structure. Further, chemical control of kinetics of swelling was coupled to biophysical control of kinetics of swelling by synthesizing hydrogels containing two types of cross-linking agents, one hydrolyzable, the other enzymatically degradable. The kinetics of swelling of cross-linked polymers was compared with the kinetics of hydrolysis of N-alkanoyl, O-methacryloylhydroxylaminemoieties incorporated into linear soluble copolymers of similar structures.
通过N，N-二甲基丙烯酰胺、叔丁基丙烯酰胺、丙烯酸、4,4'-二（甲基丙烯酰氨基）偶氮苯和N-烷酰基-O-甲基丙烯酰羟胺的共聚反应合成了新型pH敏感水凝胶。研究了烷酰基（丙酰基、己酰基和月桂酰基）的长度（以及相应的疏水性）及其在水凝胶中的含量对溶胀动力学的影响。当pH值从酸性变为中性时，N-烷酰基-O-酰基羟胺部分会发生水解。侧链水解速率取决于烷基的长度和网络结构中可水解共聚单体的含量。此外，通过合成含有两种交联剂（一种可水解，另一种可酶解）的水凝胶，将溶胀动力学的化学控制与溶胀动力学的生物物理控制相结合。将交联聚合物的溶胀动力学与掺入类似结构的线性可溶性共聚物中的N-烷酰基-O-甲基丙烯酰羟胺部分的水解动力学进行了比较。
