Cystamine-based polymers may help to achieve controlled and targeted drug delivery to the colon due to their susceptibility to breakage of the disulfide linkage in the low redox potential environment of the colon. In this study, two linear cystamine-based polymers with similar repeating units (LP1 and LP2) and a cross-linked cystamine-based polymer (BP) were synthesised and their kinetics and the various physical conditions underlying cystamine-based polymerisation were evaluated. In brief, N1, N6-bis(2-(tritylthio)ethyl)adipamide (2) was synthesised from the reaction of triphenylmethanol and cysteamine. Next, the trityl group of 2 was removed with trifluoroacetic acid and triethylsilane before proceeding to oxidative polymerisation of the end product, N1, N6-bis(2-mercaptoethyl)adipamide (3) to LP1. The Schotten-Bauman reaction was applied to synthesise LP2 and BP from the reaction of cystamine with adipoyl chloride or trimesoyl chloride. Scanning electron microscopy, energy-dispersive X-ray spectroscopy, and mapping showed that oxygen, nitrogen, sulfur, and carbon were homogenously distributed in the polymers, with LP2 and BP having less porous morphologies compared to LP1. Results of zinc-acetic acid reduction showed that all polymers began to reduce after 15 min. Moreover, all synthesised polymers resisted stomach and small intestine conditions and only degraded in the presence of bacteria in the colon environment. Thus, these polymers have great potential for drug delivery applications. LP2 and BP, which were synthesised using the Schotten-Bauman reaction, were more promising than LP1 for colon-targeted drug delivery.

中文翻译：

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用于结肠靶向药物递送的氧化还原敏感的线性和交联的基于胱胺的聚合物：设计，合成和表征。

基于胱胺的聚合物由于在结肠的低氧化还原电位环境中易受二硫键断裂的影响，因此可能有助于实现向结肠的受控和靶向药物递送。在这项研究中，合成了两个具有相似重复单元的线性基于胱胺的聚合物（LP1和LP2）和一个交联的基于胱胺的聚合物（BP），并评估了其动力学和基于胱胺的聚合的各种物理条件。简而言之，由三苯基甲醇和半胱胺的反应合成了N1，N6-双（2-（三苯硫基）乙基）己二酰胺（2）。接下来，在进行最终产物N1，N1-N6-双（2-巯基乙基）己二酰胺（3）的氧化聚合为LP1之前，用三氟乙酸和三乙基硅烷除去2的三苯甲基。Schotten-Bauman反应用于从胱胺与己二酰氯或均苯三甲酰氯的反应合成LP2和BP。扫描电子显微镜，能量色散X射线光谱法和作图表明，氧，氮，硫和碳均匀地分布在聚合物中，与LP1相比，LP2和BP的多孔形态更少。锌乙酸还原的结果表明，所有聚合物在15分钟后开始还原。此外，所有合成的聚合物均能抵抗胃和小肠疾病，并且仅在结肠环境中存在细菌时才会降解。因此，这些聚合物在药物递送应用中具有巨大潜力。使用Schotten-Bauman反应合成的LP2和BP在靶向结肠的药物递送方面比LP1更有前景。