The physiological environment is a crucial factor in biomedical systems, which can be regulated with relative ease both in vitro and in vivo. Control of pH has emerged as a powerful strategy in cancer therapy because pH has a profound effect on the interaction of a polymeric-based drug delivery system with tumor cells. In this regard, the enhancement of pH response capability was demonstrated with a 5-flourouracil (5-FU)-loaded guar gum (GG)-grafted-lysine-β-cyclodextrin (L-β-CD) drug carrier. The size, charge, morphology, and encapsulation efficiency of the 5-FU-loaded polymeric carrier were characterized for the control and sustained release of the drug. In a specific cancer pH environment, 5-FU-loaded GG-g-L-β-CD could rapidly swallow, disassemble, and release 5-FU by accepting or losing electrons. In vitro observations indicate that GG-g-L-β-CD dramatically releases 5-FU in an acidic environment rather than in a basic environment. In vitro antitumor activity tests showed that 5-FU-loaded GG-g-L-β-CD had a higher cytotoxicity against KB cells, with an IC₅₀ value of 1.38 μg ml⁻¹. The reactive oxygen species (ROS) generated by 5-FU in the KB cells showed efficient suppression of tumour cell growth. The Hoechst assay revealed the active nature of 5-FU in the cell nucleus of the KB cells. The potential mitochondrial damage by apoptosis in KB cells greatly increased cell death. Therefore, due to its active nature, the pH-sensitive 5-FU-loaded GG-g-L-β-CD carrier is a potential drug delivery system for safe and effective cancer therapy, and it can be useful for inhibiting tumour cell growth.

中文翻译：

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pH敏感的瓜尔豆胶接枝的赖氨酸-β-环糊精药物载体，可将5-氟尿嘧啶控制释放到癌细胞中†

生理环境是生物医学系统中的关键因素，可以在体外和体内相对容易地对其进行调节。在癌症治疗中，pH的控制已成为一种强有力的策略，因为pH对基于聚合物的药物递送系统与肿瘤细胞的相互作用具有深远的影响。在这方面，用负载5-氟尿嘧啶（5-FU）的瓜尔豆胶（GG）接枝的-赖氨酸-β-环糊精（L-β-CD）药物载体证明了pH响应能力的增强。载有5-FU的聚合物载体的大小，电荷，形态和包封效率可用于药物的控制和持续释放。在特定的癌症pH环境中，加载5-FU的GG- g-L-β-CD可以通过接受或丢失电子而迅速吞咽，分解并释放5-FU。体外观察表明，GG - g -L-β-CD在酸性环境而非碱性环境中会显着释放5-FU。体外抗肿瘤活性测试表明，加载5-FU的GG- g -L-β-CD对KB细胞具有更高的细胞毒性，IC ₅₀值为1.38μgml ^-1。5-FU在KB细胞中产生的活性氧（ROS）表现出对肿瘤细胞生长的有效抑制。Hoechst分析揭示了KB细胞的细胞核中5-FU的活性。KB细胞凋亡中潜在的线粒体损伤大大增加了细胞死亡。因此，由于其活性性质，pH敏感的加载有5-FU的GG- g -L-β-CD载体是用于安全有效的癌症治疗的潜在药物递送系统，可用于抑制肿瘤细胞生长。