Blanchard J
J Pharm Sci. 1982 Dec;71(12):1415-8. doi: 10.1002/jps.2600711229.
The plasma protein binding of caffeine in young and elderly males was evaluated using an ultrafiltration technique. In spite of a significantly lower plasma albumin concentration in the elderly subjects the observed percent bound (approximately 35%) was essentially identical in both subject groups. The binding of caffeine to human plasma albumin (4.5% w/v) in vitro was also examined using ultracentrifugation and it was observed to be bound to the extent of 37.8%. In both the plasma and albumin binding studies the free fraction remained constant over the range of concentrations examined. Although there was no apparent correlation between the percent bound and the albumin concentration in the plasma of either subject group the close agreement between the degree of binding of caffeine to albumin and human plasma indicates that albumin is likely the major plasma binding protein for caffeine.
采用超滤技术评估了咖啡因在年轻男性和老年男性体内的血浆蛋白结合情况。尽管老年受试者的血浆白蛋白浓度显著较低，但两个受试者组中观察到的结合百分比（约35%）基本相同。还使用超速离心法检测了咖啡因在体外与人类血浆白蛋白（4.5% w/v）的结合情况，观察到其结合程度为37.8%。在血浆和白蛋白结合研究中，在所检测的浓度范围内，游离部分保持恒定。尽管在任何一个受试者组的血浆中，结合百分比与白蛋白浓度之间均无明显相关性，但咖啡因与白蛋白及人类血浆的结合程度密切一致，这表明白蛋白可能是咖啡因的主要血浆结合蛋白。
