Othman S, al-Turk W A, Awidi A S, Daradkeh T K, Shaheen O
Faculty of Pharmacy, University of Jordan, Amman.
Drug Des Deliv. 1987 Sep;2(1):41-7.
The need for careful monitoring of plasma concentrations of phenytoin during use of the drug in the treatment of epilepsy is well recognized; there can be great intersubject variation in the absorption rate and clearance rate of the drug, and its therapeutic ratio is narrow. In this study, two methods for determining plasma phenytoin concentrations were compared. One, based on fluorescence polarisation immunoassay (FPIA), is utilised in a commercially-available kit. The other, our own modification of a published procedure, was based on high performance liquid chromatography (HPLC). The accuracy and precision of both methods were evaluated, and the coefficients of variation (C.V.) were calculated. The C.V.'s ranged from 0.71 to 1.86% for the FPIA method, and from 2.81 to 8.69% for the HPLC method. Corresponding bias values were 1.20 to 1.60%, and 2.81 to 8.69%, respectively. A good correlation coefficient (0.977) was obtained, but estimated phenytoin concentrations were significantly higher (95% confidence level) using the HPLC method. We conclude that both methods perform adequately for clinical purposes. The HPLC method is, however, less expensive than the FPIA method.
在使用苯妥英治疗癫痫期间，需要仔细监测其血浆浓度，这一点已得到广泛认可；该药物的吸收速率和清除速率在个体间可能存在很大差异，且其治疗窗较窄。在本研究中，对两种测定血浆苯妥英浓度的方法进行了比较。一种基于荧光偏振免疫分析（FPIA），用于一种市售试剂盒。另一种是我们对已发表方法的改进，基于高效液相色谱法（HPLC）。评估了两种方法的准确性和精密度，并计算了变异系数（C.V.）。FPIA方法的C.V.范围为0.71%至1.86%，HPLC方法的C.V.范围为2.81%至8.69%。相应的偏差值分别为1.20%至1.60%和2.81%至8.69%。获得了良好的相关系数（0.977），但使用HPLC方法时，苯妥英浓度估计值显著更高（95%置信水平）。我们得出结论，两种方法在临床应用中均表现良好。然而，HPLC方法比FPIA方法成本更低。
