Li Zhaohui, Fitzgerald Nicole M, Albert Zachary, Jiang Wei-Teh
Beijing Key Laboratory of Materials Utilization of Nonmetallic Minerals and Solid Wastes, National Laboratory of Mineral Materials, School of Materials Science and Technology, China University of Geosciences, Beijing, 29 Xueyuan Road, Beijing 100083, China; Geosciences Department, University of Wisconsin-Parkside, Kenosha, WI 53144, USA; Department of Earth Science, National Cheng Kung University, Tainan 70101, Taiwan.
Geosciences Department, University of Wisconsin-Parkside, Kenosha, WI 53144, USA.
Colloids Surf B Biointerfaces. 2016 Apr 1;140:67-73. doi: 10.1016/j.colsurfb.2015.11.045. Epub 2015 Dec 18.
As natural ingredients and excipients, kaolinite and talc were frequently studied for their interactions with drugs in pharmaceutical formulations. In this study, the uptake of ranitidine (RT) on these two minerals was studied under different physic-chemical conditions and the mechanism of RT uptake on these two minerals contrasted. Although the thermodynamic and kinetic RT uptake on these two minerals was similar and the RT uptake on both minerals were limited to the external surfaces only, drastic difference in RT uptake was found under different equilibrium solution pH and ionic strength conditions. As cation exchange process was strongly affected by solution pH and ionic strength, the RT uptake on kaolinite was dominated by cation exchange and electrostatic interactions, while the RT uptake on talc was more controlled by inter- and intra- molecular hydrogen bonding interactions. For kaolinite, the limiting factor for RT uptake was the specific surface area due to monolayer RT adsorption. In contract, multilayer RT uptake was found on talc surfaces. No matter which mechanism dominated RT uptake on these minerals, the interaction should not be neglected in pharmaceutical formulations should these minerals be used as additives and/or excipients.
作为天然成分和辅料，高岭土和滑石粉因其在药物制剂中与药物的相互作用而经常被研究。在本研究中，研究了雷尼替丁（RT）在这两种矿物质上在不同物理化学条件下的摄取情况，并对比了RT在这两种矿物质上的摄取机制。尽管RT在这两种矿物质上的热力学和动力学摄取情况相似，且RT在两种矿物质上的摄取都仅局限于外表面，但在不同的平衡溶液pH值和离子强度条件下，发现RT摄取存在显著差异。由于阳离子交换过程受溶液pH值和离子强度的强烈影响，RT在高岭土上的摄取主要由阳离子交换和静电相互作用主导，而RT在滑石粉上的摄取更多地受分子间和分子内氢键相互作用控制。对于高岭土，由于RT单层吸附，其摄取的限制因素是比表面积。相比之下，在滑石粉表面发现了多层RT摄取。无论哪种机制主导RT在这些矿物质上的摄取，若将这些矿物质用作添加剂和/或辅料，在药物制剂中这种相互作用都不应被忽视。
