Paxton J W, Rowell F, Ratcliffe J G, Lambie D G, Nanda R, Melville I D, Johnson R H
Eur J Clin Pharmacol. 1977;11(1):71-4. doi: 10.1007/BF00561791.
A simple, specific and rapid radioimmunoassay (RIA) method for the assessment of non-protein bound ('free') phenytoin (DPH) concentrations in mixed saliva is described. Epileptic patients on maintenance phenytoin therapy have mixed saliva phenytoin concentrations similar to 'free' drug levels measured directly in serum or cerebrospinal fluid (CSF), Salivary phenytoin levels are approximately 10% of the total serum level in treated epileptic patients and in normal subjects after ingestion of a single oral dose. The half time of disappearance of phenytoin after 100 or 300 mg doses is 12.2 +/- 3.0 (SD) h in serum and 12.3 +/- 3.2 (SD) h in saliva. This method of assessing the biologically active fraction of the drug may be particularly valuable in situations where serum protein binding is abnormal or in drug interactions. It is also non-invasive and requires small sample volumes (20mul) and may therefore be valuable in paediatric practice and in pharmacokinetic studies in which multiple venepunctures would otherwise be required.
本文描述了一种简单、特异且快速的放射免疫分析（RIA）方法，用于评估混合唾液中未结合蛋白（“游离”）的苯妥英（DPH）浓度。接受苯妥英维持治疗的癫痫患者，其混合唾液中苯妥英浓度与直接在血清或脑脊液（CSF）中测得的“游离”药物水平相似。在接受治疗的癫痫患者和正常受试者单次口服给药后，唾液中苯妥英水平约为血清总水平的10%。100或300mg剂量的苯妥英在血清中的消除半衰期为12.2±3.0（标准差）小时，在唾液中为12.3±3.2（标准差）小时。这种评估药物生物活性部分的方法在血清蛋白结合异常或存在药物相互作用的情况下可能特别有价值。它也是非侵入性的，所需样本量小（20微升），因此在儿科实践和药代动力学研究中可能很有价值，否则这些研究需要多次静脉穿刺。
