Encapsulation of platinum-based anticancer drugs inside cucurbit[n]urils provides a steric hindrance to drug degradation. This study describes an alternative strategy for the enhancement of in vitro antitumor activity of nedaplatin (NDP) by encapsulating it in the cavity of cucurbit[7]uril (CB[7]). The complexation stoichiometry, binding affinity and geometry were studied via reliable spectroscopic and physicochemical techniques. The stoichiometry of the inclusion complex was 1:1 and the stability constant (K S ) value was found to be (2.89 ± 0.26) × 10 6 M −1 at 293 K, which suggested a favorable inclusion complexation system has been formed. In vitro cytotoxicity of the free NDP and complexed NDP (NDP@CB[7]) was examined by MTT assay using three human cancer cell lines: A549, HCT116, MCF-7. Interestingly, more cytotoxicity on MCF-7 was observed for NDP@CB[7] as compared with free drugs. In addition, NDP@CB[7] showed significantly improved cytotoxicity against A549 and HCT116 cells with up to almost threefold and twofold higher cytotoxicity than that of free NDP, indicating that the encapsulation of NDP in CB[7] can enhance the cytotoxicity of NDP in tested cancer cell lines. The formed species are shown to be stabilized in solution and the host–guest complexation between NDP and CB[7] may allow this strategy to be effective for potential use in drug delivery.

中文翻译：

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用于提高体外抗肿瘤活性的奈达铂与葫芦[7]脲的主客体包含系统

将基于铂的抗癌药物封装在葫芦 [n] 脲内为药物降解提供了空间位阻。本研究描述了一种通过将奈达铂 (NDP) 封装在葫芦 [7] 脲 (CB[7]) 腔中来增强其体外抗肿瘤活性的替代策略。通过可靠的光谱和物理化学技术研究了络合化学计量、结合亲和力和几何形状。包合物的化学计量比为 1:1，在 293 K 时的稳定性常数 (KS ) 值为 (2.89 ± 0.26) × 10 6 M -1 ，表明形成了有利的包合物体系。使用三种人类癌细胞系：A549、HCT116、MCF-7，通过 MTT 法检测游离 NDP 和复合 NDP（NDP@CB[7]）的体外细胞毒性。有趣的是，与游离药物相比，NDP@CB[7] 对 MCF-7 的细胞毒性更大。此外，NDP@CB[7] 对 A549 和 HCT116 细胞的细胞毒性显着提高，细胞毒性比游离 NDP 高近 3 倍和 2 倍，表明 NDP 包裹在 CB[7] 中可以增强 NDP 的细胞毒性在测试的癌细胞系中。所形成的物质在溶液中是稳定的，NDP 和 CB 之间的主客体复合 [7] 可能使该策略有效用于药物递送的潜在用途。表明 NDP 包裹在 CB[7] 中可以增强 NDP 在测试癌细胞系中的细胞毒性。所形成的物质在溶液中是稳定的，NDP 和 CB 之间的主客体复合 [7] 可能使该策略有效用于药物递送的潜在用途。表明 NDP 包裹在 CB[7] 中可以增强 NDP 在测试癌细胞系中的细胞毒性。所形成的物质在溶液中是稳定的，NDP 和 CB 之间的主客体复合 [7] 可能使这种策略有效地用于药物递送。