Ha C E, Petersen C E, Park D S, Harohalli K, Bhagavan N V
Department of Biochemistry and Biophysics, John A. Burns School of Medicine, University of Hawaii, Honolulu, Hawaii 96822, USA.
J Biomed Sci. 2000 Mar-Apr;7(2):114-21. doi: 10.1007/BF02256617.
Ethanol effects on warfarin binding to human serum albumin (HSA) have been studied by equilibrium dialysis and fluorescence methods at pH 7.4 in phosphate-buffered saline at 37 degrees C. In the presence of various amounts of ethanol fluorescence intensity of bound warfarin decreased significantly but this intensity reduction was not solely from displacement of bound warfarin from HSA. By comparing fluorescence and equilibrium dialysis data we concluded that fluorescence intensity reduction of warfarin was mainly the result of changes in the surrounding environment of the warfarin binding site by ethanol interaction with HSA and that displacement of bound warfarin was not significant compared to the fluorescence intensity changes. The dissociation constant of warfarin binding to HSA decreased with an increasing amount of ethanol. From the changes in fluorescence intensity upon warfarin binding to HSA with the presence of ethanol ranging from 0 to 5.0% the following dissociation constants (Kd) were determined: 0% ethanol 5.39 +/- 0.2 microM, 0.1% ethanol 5.86 +/- 0.1 microM, 0.3% ethanol 5.83 +/- 0.2 microM, 0.5% ethanol 6.76 +/- 0.1 microM, 1% ethanol 7.01 +/- 0.1 microM, 3% ethanol 9.9 +/- 0.7 microM, 5% ethanol 13.01 +/- 0.1 microM. From the equilibrium dialysis with the same ranges of ethanol presence the following Kd values were obtained: 0% ethanol 6. 62 +/- 1.6 microM, 0.1% ethanol 6.81 +/- 1.1 microM, 0.3% ethanol 8. 26 +/- 2.5 microM, 0.5% ethanol 8.86 +/- 1.9 microM, 1% ethanol 11. 01 +/- 4.2 microM, 3% ethanol 20.75 +/- 2.4 microM, 5% ethanol 21.67 +/- 2.2 microM. The results suggest that warfarin bound to HSA was displaced by ethanol. These data indicate that ethanol influence on warfarin binding to HSA may alter the pharmacokinetics of warfarin.
在37℃的磷酸盐缓冲盐溶液（pH 7.4）中，通过平衡透析和荧光法研究了乙醇对华法林与人血清白蛋白（HSA）结合的影响。在存在不同量乙醇的情况下，结合型华法林的荧光强度显著降低，但这种强度降低并非仅仅是由于结合型华法林从HSA上被置换所致。通过比较荧光和平衡透析数据，我们得出结论，华法林荧光强度降低主要是乙醇与HSA相互作用导致华法林结合位点周围环境变化的结果，并且与荧光强度变化相比，结合型华法林的置换并不显著。华法林与HSA的解离常数随着乙醇量的增加而降低。根据华法林在0%至5.0%乙醇存在下与HSA结合时荧光强度的变化，确定了以下解离常数（Kd）：0%乙醇时为5.39±0.2微摩尔，0.1%乙醇时为5.86±0.1微摩尔，0.3%乙醇时为5.83±0.2微摩尔，0.5%乙醇时为6.76±0.1微摩尔，1%乙醇时为7.01±0.1微摩尔，3%乙醇时为9.9±0.7微摩尔，5%乙醇时为13.01±0.1微摩尔。在相同乙醇存在范围内进行平衡透析，得到以下Kd值：0%乙醇时为6.62±1.6微摩尔，0.1%乙醇时为6.81±1.1微摩尔，0.3%乙醇时为8.26±2.5微摩尔，0.5%乙醇时为8.86±1.9微摩尔，1%乙醇时为11.01±4.2微摩尔，3%乙醇时为20.75±2.4微摩尔，5%乙醇时为21.67±2.2微摩尔。结果表明，结合到HSA上的华法林被乙醇置换。这些数据表明，乙醇对华法林与HSA结合的影响可能会改变华法林的药代动力学。
