The adsorption of two pharmaceuticals, carbamazepine and paracetamol, onto the expandable clay mineral saponite has been studied through the combination of kinetic experiments, X-ray diffraction, and theoretical modeling. Kinetic experiments indicate low adsorption for carbamazepine and paracetamol on expandable smectite clay. Accordingly, X-ray diffraction experiments show that neither compound enters smectite interlayer space. Molecular dynamics simulations were carried out to understand the interactions between the two pharmaceuticals and the saponite basal surface in the presence of Na⁺ cations. Calculations reveal that paracetamol almost does not coordinate solution cations, whereas a rather low coordination to cation is observed for carbamazepine. As a result, the adsorption onto the clay surface results mainly from van der Waals interactions for both pharmaceuticals. Carbamazepine does adsorb the surface via two configurations, one involving cation coordination, which corresponds to a rather stable adsorption compared to paracetamol. This is confirmed by structural analyses completed with desorption free energy profile.

中文翻译：

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蒙脱石粘土矿物上药物的吸附：组合的实验和理论研究。

通过动力学实验，X射线衍射和理论模型的结合，研究了卡马西平和扑热息痛两种药物在可膨胀粘土矿物皂石上的吸附。动力学实验表明，卡马西平和扑热息痛在可膨胀蒙脱石粘土上的吸附较低。因此，X射线衍射实验表明没有化合物进入蒙脱石层间空间。进行了分子动力学模拟，以了解存在Na ⁺的情况下两种药物与皂石基底表面之间的相互作用。阳离子。计算表明，扑热息痛几乎不与溶液中的阳离子配位，而卡马西平对阳离子的配位较低。结果，两种药物在粘土表面的吸附主要是由于范德华相互作用。卡马西平确实通过两种构型吸附表面，一种构型涉及阳离子配位，与扑热息痛相比，这相当稳定。通过具有解吸自由能分布的结构分析证实了这一点。