A design strategy for macromolecular prodrugs is described, that are expected to exhibit robust activity against most solid tumor types while resulting in minimal toxicities to normal tissues. This approach exploits the enhanced permeability, and retention (EPR) effect, and utilizes carefully engineered rate constants to selectively target tumor tissue with short-lived cytotoxic moieties. EPR based tumor accumulation (half-life ~ 15 h) is dependent upon the ubiquitous abnormal solid tumor capillary morphology and is expected to be independent of individual tumor cell genetic variability that leads to resistance to molecularly targeted agents. The macromolecular sulfonylhydrazine-based prodrugs hydrolyze spontaneously with long half-life values (~10 h to >300 h dependent upon their structure) resulting in the majority of the 1,2-bis(sulfonyl)-1-alkylhydrazines (BSHs) cytotoxic warhead being released only after tumor sequestration. The very short half-life (seconds) of the finally liberated BSHs localizes the cytotoxic stress to the tumor target site by allowing insufficient time for escape. Thus, short lifespan anticancer species are liberated, and exhibit their activity largely within the tumor target. The abnormal tumor cell membrane pH gradients favor the uptake of BSHs compared to that of normal cells, further enhancing their selectivity. The reliance on physicochemical/chemical kinetic parameters and the EPR effect is expected to reduce response variability, and the acquisition of resistance.
本文描述了一种大分子前药的设计策略,预计这些前药在对大多数实体肿瘤类型表现出强大活性的同时,对正常组织的毒性最小。该方法利用了增强渗透性和滞留(EPR)效应,并利用精心设计的速率常数,有选择性地针对肿瘤组织,使用短寿命细胞毒性物质。EPR基于肿瘤毛细血管形态的普遍异常,肿瘤积累(半衰期约为15小时)预计与导致分子靶向药物抵抗的个体肿瘤细胞遗传变异无关。基于磺酰
肼基的大分子前药具有长半衰期值(约为10小时至> 300小时,取决于其结构),可自发
水解,导致大部分1,2-双(磺酰基)-1-烷基
肼(BSHs)细胞毒性弹头仅在肿瘤隔离后释放。最后释放的BSHs的非常短的半衰期(秒)通过允许不足的时间逃脱,将细胞毒性应激定位于肿瘤靶点。异常的肿瘤细胞膜pH梯度有利于BSHs的摄取,相比正常细胞,进一步增强了它们的选择性。预计依赖于物理
化学/
化学动力学参数和EPR效应将减少反应变异和获得抗性。