ABSTRACT
The bacterial cell division protein FtsZ represents a novel antibiotic target that has yet to be exploited clinically. The benzamide PC190723 was among the first FtsZ-targeting compounds to exhibit
in vivo
efficacy in a murine infection model system. Despite its initial promise, the poor formulation properties of the compound have limited its potential for clinical development. We describe here the development of an
N
-Mannich base derivative of PC190723 with enhanced drug-like properties and oral
in vivo
efficacy. The
N
-Mannich base derivative (TXY436) is ∼100-fold more soluble than PC190723 in an acidic aqueous vehicle (10 mM citrate, pH 2.6) suitable for oral
in vivo
administration. At physiological pH (7.4), TXY436 acts as a prodrug, converting to PC190723 with a conversion half-life of 18.2 ± 1.6 min. Pharmacokinetic analysis following intravenous administration of TXY436 into mice yielded elimination half-lives of 0.26 and 0.96 h for the TXY436 prodrug and its PC190723 product, respectively. In addition, TXY436 was found to be orally bioavailable and associated with significant extravascular distribution. Using a mouse model of systemic infection with methicillin-sensitive
Staphylococcus aureus
or methicillin-resistant
S. aureus
, we show that TXY436 is efficacious
in vivo
upon oral administration. In contrast, the oral administration of PC190723 was not efficacious. Mammalian cytotoxicity studies of TXY436 using Vero cells revealed an absence of toxicity up to compound concentrations at least 64 times greater than those associated with antistaphylococcal activity. These collective properties make TXY436 a worthy candidate for further investigation as a clinically useful agent for the treatment of staphylococcal infections.
摘要
细菌细胞分裂蛋白 FtsZ 是一种新型抗生素靶标,但尚未在临床上得到应用。苯甲酰胺 PC190723 是首批 FtsZ 靶向化合物之一,在
体内
小鼠感染模型系统中显示出体内疗效。尽管该化合物最初很有希望,但其不良的制剂特性限制了其临床开发的潜力。我们在此介绍一种
N
-曼尼希碱衍生物的开发情况。
体内
疗效。其
N
-曼尼希碱衍生物(TXY436)在酸性水溶液载体(10 mM 柠檬酸盐,pH 值 2.6)中的溶解度比 PC190723 高出 100 倍,适合口服和体内试验。
体内
给药。在生理 pH 值(7.4)下,TXY436 可作为原药转化为 PC190723,转化半衰期为 18.2 ± 1.6 分钟。小鼠静脉注射 TXY436 后进行药代动力学分析,发现 TXY436 原药及其 PC190723 产物的消除半衰期分别为 0.26 和 0.96 小时。此外,研究还发现 TXY436 具有口服生物利用度,并有显著的血管外分布。使用对甲氧西林敏感的金黄色葡萄球菌全身感染小鼠模型
金黄色葡萄球菌
或耐甲氧西林
金黄色葡萄球菌
的小鼠模型表明,TXY436 在体内具有疗效
在体内
口服 TXY436 有疗效。相比之下,口服 PC190723 没有疗效。利用 Vero 细胞对 TXY436 进行的哺乳动物细胞毒性研究表明,在化合物浓度至少是抗葡萄球菌活性浓度的 64 倍时,TXY436 没有毒性。这些综合特性使 TXY436 成为治疗葡萄球菌感染的临床有用药物,值得进一步研究。