A series of atomistic molecular dynamics simulations were performed for investigating the interactions between three different testosterone-based compounds (testosterone (T), testosterone propionate (TP) and testosterone enanthate (TE)) and sodium dodecyl sulphate (SDS) and ammonium dodecyl sulphate (ADS) monolayers, which vary only in the sodium or ammonium counterions used to neutralise the sulphate headgroup. These simulations were used to investigate how the structural and interfacial properties of the monolayer were affected by changing the number of drug molecules present per monolayer, and the chemical nature of the surfactant counterions and the testosterone-based compounds. Our results show that the structure of the interfacial water layer is affected by the change of the counterion but not the chemistry of the drug molecules. As a result of the difference in their chemical structure, the T, TP and TE drug molecules prefer different locations and orientations within the monolayers. Finally, we observed that the hydration of the drug molecules encapsulated within the ADS monolayers is significantly less than when they are encapsulated within the SDS monolayers. Understanding the role that the counterion and the chemistry of the drug molecules play in these systems provides us with a detailed description of the interactions that cause ADS micelles to encapsulate significantly less drug molecules than SDS micelles, which we have recently observed experimentally.

中文翻译：

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睾酮基化合物与十二烷基硫酸盐在空气-水界面处的相互作用†

进行了一系列原子分子动力学模拟，以研究三种不同的基于睾丸酮的化合物（睾丸酮（T），丙酸睾丸酮（TP）和庚酸酯庚酸酯（TE）），十二烷基硫酸钠（SDS）和十二烷基硫酸铵（ ADS）单层，仅在用于中和硫酸根基的钠或铵抗衡离子上有所不同。这些模拟用于研究如何通过改变每个单层中存在的药物分子数量以及表面活性剂抗衡离子和睾丸激素类化合物的化学性质来影响单层的结构和界面特性。我们的结果表明界面水层的结构受抗衡离子变化的影响，但不受药物分子化学性质的影响。由于它们的化学结构不同，T，TP和TE药物分子在单分子层中更喜欢不同的位置和方向。最后，我们观察到，包裹在ADS单层内的药物分子的水合作用明显少于包裹在SDS单层内的药物分子的水合作用。理解药物分子的抗衡离子和化学作用在这些系统中的作用，为我们提供了导致ADS胶束封装的药物分子比SDS胶束少得多的药物分子的相互作用的详细描述，我们最近通过实验观察到。我们观察到，包裹在ADS单层中的药物分子的水合作用明显少于包裹在SDS单层中的药物分子的水合作用。理解药物分子的抗衡离子和化学作用在这些系统中的作用，为我们提供了导致ADS胶束封装的药物分子比SDS胶束少得多的药物分子的相互作用的详细描述，我们最近通过实验观察到。我们观察到，包裹在ADS单层中的药物分子的水合作用明显少于包裹在SDS单层中的药物分子的水合作用。理解药物分子的抗衡离子和化学作用在这些系统中的作用，为我们提供了导致ADS胶束封装的药物分子比SDS胶束少得多的药物分子的相互作用的详细描述，我们最近通过实验观察到。