de la Peña L, Gómez-Hens A, Pérez-Bendito D
Department of Analytical Chemistry, Faculty of Sciences, University of Córdoba, Córdoba, Spain.
Talanta. 1994 Nov;41(11):1895-901. doi: 10.1016/0039-9140(94)00144-8.
The oxidation reactions of methotrimeprazine and thioridazine by iron(III) were used to develop kinetic methods based on measurements of the formation rate of the corresponding coloured phenothiazinyl free radicals. The calibration graphs were linear over the range 0.8-60 microg/ml for methotrimeprazine and 1.1-60 microg/ml for thioridazine. The relative standard deviation was 1.1-3.4%. The method was used to determine the analytes in commercially available pharmaceutical preparations. The different absorption maxima of the oxidation products formed and also the different, high initial rates of the reactions for both analytes allow their simultaneous determination by using a stopped-flow module coupled to a diode-array spectrophotometric detector. Reaction rate and absorbance increment measurements of the kinetic curves obtained were used to resolve mixtures of both phenothiazines by using the proportional-equation method and establishing three different equation systems that allowed the results obtained in each case to be compared. Mixtures of methotrimeprazine and thioridazine in ratios between 8:1 and 1:8 were satisfactorily resolved.
利用铁（III）对甲氧异丁嗪和硫利达嗪的氧化反应，基于对相应有色吩噻嗪基自由基形成速率的测量来开发动力学方法。对于甲氧异丁嗪，校准曲线在0.8 - 60微克/毫升范围内呈线性，对于硫利达嗪，在1.1 - 60微克/毫升范围内呈线性。相对标准偏差为1.1 - 3.4%。该方法用于测定市售药物制剂中的分析物。两种分析物形成的氧化产物具有不同的吸收最大值，且反应的初始速率也不同，这使得可以使用与二极管阵列分光光度检测器相连的停流模块同时测定它们。通过使用比例方程法并建立三个不同的方程组，对所获得的动力学曲线的反应速率和吸光度增量测量结果进行处理，以便比较每种情况下获得的结果。甲氧异丁嗪和硫利达嗪比例在8:1至1:8之间的混合物得到了满意的分离。
