SSPC, the Science Foundation Ireland Research Centre for Pharmaceuticals, Department of Chemical Sciences, Bernal Institute, University of Limerick, Ireland.
SSPC, the Science Foundation Ireland Research Centre for Pharmaceuticals, Department of Chemical Sciences, Bernal Institute, University of Limerick, Ireland.
Eur J Pharm Biopharm. 2022 Feb;171:29-38. doi: 10.1016/j.ejpb.2021.12.010. Epub 2022 Jan 2.
In order to develop bacteriocins, like the lantibiotic nisin A, into effective alternatives to existing antibiotics, their biophysical and physicochemical properties must first be assessed, from solubility, to susceptibility and absorption. It has been well established that formulation strategies at early drug development stages can be crucial for successful outcomes during preclinical and clinical phases of development, particularly for molecules with challenging physicochemical properties. This work elucidates the physicochemical challenges of nisin A in terms of its susceptibility to digestive enzymes like pepsin, pancreatin and proteinase K and its poor solubility at physiological pHs. Low solution concentrations, below the minimum inhibitory concentration against Staphylococcus aureus, were obtained in phosphate buffered saline (PBS, pH 7.4) and in fasted state simulated intestinal fluid (FaSSIF, pH 6.5), while higher solubilities at more acidic pH's such as in a KCl/HCl buffer (pH 2) and in fasted state simulated gastric fluid (FaSSGF, pH 1.6) are observed. Tween® 80 (0.01% v/v) significantly increased the solution concentration of nisin A in PBS (pH 7.4, 24 hr). Pancreatin doubled nisin A's solution concentration at pH 7.4 (PBS) but reduced its' inhibitory activity to ∼ 20%, and pepsin almost completely degraded nisin (after 24 hr), but retained activity at biologically relevant exposure times (∼15 min). Harnessing synergism between nisin A and either glycol chitosan or ε-poly lysine, combined with the solubilizing effect of Tween®, increased the antimicrobial activity of nisin A six fold in an in vitro oral administration model.
为了将细菌素（如羊毛硫抗生素类尼生素 A）开发为现有抗生素的有效替代品，必须首先评估它们的物理化学特性，从溶解度、敏感性和吸收性等方面进行评估。早期药物开发阶段的制剂策略对于开发的临床前和临床阶段的成功至关重要，这一点已经得到充分证实，特别是对于具有挑战性的物理化学特性的分子。这项工作阐明了尼生素 A 在消化酶（如胃蛋白酶、胰酶和蛋白酶 K）敏感性以及在生理 pH 值下溶解度差方面的物理化学挑战。在磷酸盐缓冲盐水（PBS，pH7.4）和空腹模拟肠液（FaSSIF，pH6.5）中，获得了低于金黄色葡萄球菌最低抑菌浓度的低溶液浓度，而在更酸性的 pH 值（如 KCl/HCl 缓冲液（pH2）和空腹模拟胃液（FaSSGF，pH1.6）中观察到更高的溶解度。吐温®80（0.01%v/v）显著增加了尼生素 A 在 PBS（pH7.4，24 小时）中的溶液浓度。胰酶使尼生素 A 在 pH7.4（PBS）下的溶液浓度增加了一倍，但将其抑制活性降低至约 20%，而胃蛋白酶几乎完全降解了尼生素 A（24 小时后），但在生物学相关暴露时间（约 15 分钟）内仍保持活性。利用尼生素 A 与壳聚糖或 ε-聚赖氨酸之间的协同作用，结合吐温®的增溶作用，在体外口服给药模型中使尼生素 A 的抗菌活性提高了六倍。
