Center for Drug Delivery System, Shanghai Institute of Materia Medica, State Key Laboratory of Drug Research, Chinese Academy of Sciences, Shanghai 201203, China.
J Chromatogr A. 2013 Aug 30;1305:139-48. doi: 10.1016/j.chroma.2013.07.010. Epub 2013 Jul 7.
It is challenging and extremely difficult to measure the kinetics of supramolecular systems with extensive, weak binding (Ka<10(5)M(-1)), and fast dissociation, such as those composed of cyclodextrins and drugs. In this study, a modified peak profiling method based on high performance affinity chromatography (HPAC) was established to determine the dissociation rate constant of cyclodextrin supramolecular systems. The interactions of β-cyclodextrin with acetaminophen and sertraline were used to exemplify the method. The retention times, variances and the plate heights of the peaks for acetaminophen or sertraline, conventional non-retained substance (H2O) on the β-cyclodextrin bonded column and a control column were determined at four flow rates under linear elution conditions. Then, plate heights for the theoretical non-retained substance were estimated by the modified HPAC method, in consideration of the diffusion and stagnant mobile phase mass transfer. As a result, apparent dissociation rate constants of 1.82 (±0.01)s(-1) and 3.55 (±0.37)s(-1) were estimated for acetaminophen and sertraline respectively at pH 6.8 and 25°C with multiple flow rates. Following subtraction of the non-specific binding with the support, dissociation rate constants were estimated as 1.78 (±0.00) and 1.91 (±0.02)s(-1) for acetaminophen and sertraline, respectively. These results for acetaminophen and sertraline were in good agreement with the magnitude of the rate constants for other drugs determined by capillary electrophoresis reported in the literature and the peak fitting method we performed. The method described in this work is thought to be suitable for other supramolecules, with relatively weak, fast and extensive interactions.
用高效亲和色谱（HPAC）建立了一种改进的峰形分析方法来测定环糊精超分子体系的离解速率常数。以β-环糊精与扑热息痛和舍曲林的相互作用为例对该方法进行了说明。在 pH 6.8 和 25°C 下，用四种流速在线洗脱条件下，测定了β-环糊精键合柱和对照柱上扑热息痛或舍曲林、常规非保留物质（H2O）的保留时间、峰方差和塔板高度，以及理论上非保留物质的塔板高度。然后，通过改进的 HPAC 方法考虑扩散和停滞流动相质量传递来估计理论上非保留物质的塔板高度。结果表明，在 pH 6.8 和 25°C 下，用四种流速，分别得到了扑热息痛和舍曲林的表观离解速率常数为 1.82（±0.01）s-1和 3.55（±0.37）s-1。扣除与载体的非特异性结合后，扑热息痛和舍曲林的离解速率常数分别估计为 1.78（±0.00）和 1.91（±0.02）s-1。这些扑热息痛和舍曲林的结果与文献中报道的毛细管电泳法测定的其他药物的速率常数的量级以及我们进行的峰拟合方法相符。本工作中描述的方法被认为适用于具有相对较弱、快速和广泛相互作用的其他超分子。
