Barth N, Alván G, Borgå O, Sjöqvist F
Clin Pharmacokinet. 1976 Nov-Dec;1(6):444-52. doi: 10.2165/00003088-197601060-00004.
Plasma protein binding of phenytoin (diphenylhydantoin) in 63 epileptic patients was investigated with an ultrafiltration technique at room temperature using 14C-labelled phenytoin. A strong correlation was found between the total and the unbound drug concentration (r = 0.97, p less than 0.001). The unbound phenytoin fraction was 7.1 +/- 1.0% with a range of 4.9 to 10.2%. This variation is considerably less than that reported recently by different authors. Individual phenytoin binding was reproducible when the determination was repeated several weeks later. Salivary phenytoin concentrations in 33 epileptic patients were significantly correlated to the unbound (r = 0.83) and total concentrations (r = 0.82) of phenytoin in plasma. This study confirms that the clinical practice of monitoring total phenytoin plasma concentrations is sufficient, since the unbound phenytoin fraction has only a 2-fold interindividual variation in epileptic patients, provided that they do not suffer from renal or hepatic disease.
采用超滤技术，在室温下用14C标记的苯妥英对63例癫痫患者的苯妥英（二苯乙内酰脲）血浆蛋白结合情况进行了研究。发现总药物浓度与游离药物浓度之间存在强相关性（r = 0.97，p < 0.001）。游离苯妥英分数为7.1±1.0%，范围为4.9%至10.2%。这种变化远小于不同作者最近报道的情况。当几周后重复测定时，个体苯妥英结合情况具有可重复性。33例癫痫患者的唾液苯妥英浓度与血浆中苯妥英的游离浓度（r = 0.83）和总浓度（r = 0.82）显著相关。本研究证实，监测苯妥英血浆总浓度的临床实践就足够了，因为在癫痫患者中，游离苯妥英分数的个体间差异仅为2倍，前提是他们没有肾脏或肝脏疾病。
