Institute of Physics, University of Silesia, SMCEBI, 75 Pulku Piechoty 1A, 41-500 Chorzow, Poland; School of Pharmacy and Pharmaceutical Sciences, Trinity College Dublin, College Green, Dublin 2, Ireland.
School of Pharmacy and Pharmaceutical Sciences, Trinity College Dublin, College Green, Dublin 2, Ireland.
Eur J Pharm Sci. 2019 Jun 15;134:93-101. doi: 10.1016/j.ejps.2019.04.014. Epub 2019 Apr 13.
In this paper, we investigate the temperature-dependent relaxation dynamics in the glassy and supercooled liquid state of dipolar and ionic eutectic mixtures made of two anesthetic agents (lidocaine and prilocaine) and their hydrochloride salts, respectively. In addition to eutectic phases containing 1:1 and 4:1 mol/mol of LD/PRL and LD-HCl/PRL-HCl, respectively, the relaxation properties of non-eutectic compositions and parent compounds are also studied. We found that electrostatic long-range forces determine strongly the dielectric and mechanical response of eutectic material. As a result of Coulomb interactions between ion pairs, an additional β-relaxation mode was found in the dielectric spectra of glassy LD-HCl/PRL-HCl mixtures. On the other hand, the studies of relaxation dynamics of ionic and non-ionic mixtures at T > T revealed a continuous decrease of both fragility m and the length scale of dynamic heterogeneity N(T), with simultaneous growth of T, when the electrostatics forces appear. At the same time, we found the charge transport being decoupled from structural dynamics in all studied ionic binary mixtures that is due to the fast proton hopping. However, the efficiency of proton transport is dropping down with an increase of T.
在本文中，我们研究了由两种麻醉剂（利多卡因和丙胺卡因）及其盐酸盐分别制成的偶极和离子共晶混合物的玻璃态和过冷液体态中与温度相关的弛豫动力学。除了分别包含 1:1 和 4:1 mol/mol LD/PRL 和 LD-HCl/PRL-HCl 的共晶相之外，还研究了非共晶成分和母体化合物的弛豫特性。我们发现静电远程力强烈决定了共晶材料的介电和力学响应。由于离子对之间的库仑相互作用，在玻璃态 LD-HCl/PRL-HCl 混合物的介电谱中发现了额外的β弛豫模式。另一方面，在 T>T 时对离子和非离子混合物的弛豫动力学研究表明，当静电作用力出现时，m 和动态不均匀性的长度尺度 N(T) 的两个脆性均连续减小，同时 T 增加。同时，我们发现所有研究的离子二元混合物中的电荷输运与结构动力学解耦，这是由于质子快速跳跃。然而，随着 T 的增加，质子传输的效率会下降。
