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通过构建卡托普利插层锌铝水滑石的周期性模型,利用分子动力学方法对体系的结构参数和水合过程进行模拟。结果表明,随着水含量的升高,层间距d_c呈线性增加,拟合方程为d_c=0.084Nw+1.498(0≤Nw≤16,r~2=0.996)。当水含量N_w=5~6时,d_c值与实验表征结果相吻合,说明体系的实际水含量较低。由氢键模拟可以预测体系的水合历程为:水分子首先衔接阴离子和层板,然后逐渐将阴离子和层板分隔,最后在层板与阴离子之间排布成层。水合能值逐渐升高并趋于平衡,但平衡值仍低于体相水的势能,说明体系在高水含量的环境中仍能持续吸水膨胀。卡托普利的缓释历程可通过其水合性质来解释,其之所以释放缓慢且饱和释放值为72%,与体系平衡水合能和氢键形成规律有关,平衡水合能与体相水的势能值越接近,层间药物分子的缓释效果将越明显。
By constructing a periodic model of captopril intercalated zinc-aluminum hydrotalcite, the structural parameters and hydration process of the system were simulated by molecular dynamics method. The results show that the d_c layer spacing increases linearly with the increase of water content. The fitting equation is d_c = 0.084Nw + 1.498 (0≤Nw≤16, r_2 = 0.996). When the water content N_w = 5 ~ 6, d_c value is consistent with the experimental characterization results, indicating that the actual water content of the system is low. Hydrogen bond simulation can predict the hydration process of the system as follows: the water molecule first joins the anion and the plate, and then separates the anion and the plate gradually, and finally layers between the plate and the anion. Hydration energy value gradually increased and tends to balance, but the equilibrium value is still lower than the potential energy of bulk water, indicating that the system can continue to absorb water swelling in high water content environment. The slow release course of captopril can be explained by its hydration properties. The reason why captopril released slowly and the release value of saturation is 72%, which is related to the equilibrium hydration energy and hydrogen bond formation regularity of the system, balances the potential energy of hydration energy and bulk water The closer the value, the more effective the sustained-release effect of the inter-layer drug molecules will be.