Vasquez Jacob M, Vu Andrew, Schultz Jerome S, Vullev Valentine I
Department of Bioengineering, University of California, Riverside, Riverside, CA 92521, USA.
Biotechnol Prog. 2009 Jul-Aug;25(4):906-14. doi: 10.1002/btpr.188.
Warfarin is the most common agent used for control and prevention of venous as well as arterial thromboembolism (blood clots). In aqueous media, warfarin forms inclusion complexes with a family of cyclic oligosaccharides, alpha, beta, gamma-cyclodextrins (CD). The formation of these complexes results in enhancement of the fluorescence of warfarin. Such spectroscopic changes offer a venue for the development of bioanalytical methodologies for warfarin quantification in biological liquids. We characterized the photophysical properties of warfarin in solvents with varying polarity and viscosity. The fluorescence quantum yield of warfarin correlated: (1) strongly with the solvent viscosity (R = 0.979) and (2) weakly with the solvent polarity (R = 0.118). These findings indicate that it is the change of the viscosity, rather than polarity, of the microenvironment that causes the fluorescence enhancement of warfarin upon binding to beta-CD. Utilizing the observed fluorescence enhancement in fluorescence titration measurements, the binding constants of warfarin to beta-CD were obtained (2.6 x 10(2) M(-1)-3.7 x 10(2) M(-1)). Using multivariable linear analysis, we extracted the stoichiometry of warfarin-beta-CD interaction (1:1).
华法林是用于控制和预防静脉及动脉血栓栓塞（血凝块）的最常用药物。在水性介质中，华法林与一类环状寡糖，即α、β、γ-环糊精（CD）形成包合物。这些复合物的形成导致华法林荧光增强。这种光谱变化为开发用于定量生物液体中华法林的生物分析方法提供了途径。我们表征了华法林在具有不同极性和粘度的溶剂中的光物理性质。华法林的荧光量子产率与：（1）溶剂粘度密切相关（R = 0.979），（2）与溶剂极性弱相关（R = 0.118）。这些发现表明，是微环境粘度的变化而非极性的变化导致华法林与β-环糊精结合后荧光增强。利用荧光滴定测量中观察到的荧光增强，获得了华法林与β-环糊精的结合常数（2.6×10² M⁻¹ - 3.7×10² M⁻¹）。通过多变量线性分析，我们得出了华法林与β-环糊精相互作用的化学计量比（1:1）。
