Determination of drug-plasma protein binding kinetics and equilibria by chromatographic profiling: Exemplification of the method using L-tryptophan and albumin
Determination of drug-plasma protein binding kinetics and equilibria by chromatographic profiling: Exemplification of the method using L-tryptophan and albumin
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DOI：
10.1021/ac010643c
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发表时间：
2002-01-15
影响因子：
7.4
通讯作者：
Francis, PL
中科院分区：
文献类型：
--
作者：
Talbert, AM;Tranter, GE;Francis, PL
药物-血浆蛋白结合可能极大地影响血浆携带药物的生物利用度和代谢，结合形式被部分保护免受未结合药物的代谢命运。传统上，平衡值（例如，结合百分比）以使体内现象合理化。然而，这些研究忽略了动力学的影响。基于固定化蛋白质色谱柱和高效液相色谱法，建立了一种快速测定动力学速率常数和平衡常数的方法。通过测量保留和未保留化合物的色谱图（位置和宽度），可以直接确定速率和平衡常数。本文给出了L-色氨酸与人血清白蛋白结合的结果，以验证该方法。由此，在37 ℃、pH7.4的水溶液环境中，测定缔合平衡常数（K-a）、缔合和解离速率常数（分别为k（a）和k（d）），分别为0.84 × 10（4）M-1、5.8 × 10（4）M-1 s（-1）和6.9 s（-1）。这些结果与以前发表的结果相比毫不逊色。所述方法可用于基于定量结构-性质关系的合理药物发现或药物药代动力学的合理化。
Drug-plasma protein binding may greatly influence the bioavailability and metabolism of a plasma-borne drug, the bound form being partially protected from the metabolic fate of the unbound drug. Traditionally, equilibrium values (e.g., percentage binding) for drug-protein binding have been measured to rationalize in vivo phenomena. However, such studies overlook the influence of kinetics. A rapid method of simultaneously determining kinetic rate constants and equilibrium constants from chromatographic profiles has been developed, based on the use of immobilized protein columns and HPLC. By measuring the chromatographic profiles (the position and width) of a retained and an unretained compound one can directly determine both the rate and equilibrium constants. Results are presented for the binding of L-tryptophan to human serum albumin to exemplify the method. The association equilibrium constant (K-a) and the association and dissociation rate constants (k(a) and k(d), respectively) were thereby measured in an aqueous pH 7.4 environment at 37 degreesC as 0.84 10(4) M-1, 5.8 10(4) M-1 s(-1), and 6.9 s(-1), respectively. These compare favorably with previously published results. The described method may be used in quantitative structure-property relationship-based rational drug discovery or for the rationalization of drug pharmacokinetics.