Elmosallamy Mohamed A F, Amin Alaa S
Chemistry Department, Faculty of Science, Zagazig University.
Anal Sci. 2014;30(3):419-25. doi: 10.2116/analsci.30.419.
New, simple and convenient potentiometric and spectrophotometric methods are described for the determination of dextromethorphan hydrobromide (DXM) in pharmaceutical preparations. The potentiometric technique is based on developing a potentiometric sensor incorporating the dextromethorphan tetrakis(p-chlorophenyl)borate ion-pair complex as an electroactive species in a plasticized PVC matrix membrane with o-nitophenyl octyl ether or dioctyl phthalate. The sensor shows a rapid near Nernstian response of over 1 × 10(-5) - 1 × 10(-2) mol L(-1) dextromethorphan in the pH range of 3.0 - 9.0. The detection limit is 2 × 10(-6) mol L(-1) DXM and the response time is instantaneous (2 s). The proposed spectrophotometric technique involves the reaction of DXM with eriochrom black T (EBT) to form an ion-associate complex. Solvent extraction is used to improve the selectivity of the method. The optimal extraction and reaction conditions have been studied, and the analytical characteristics of the method have been obtained. Linearity is obeyed in the range of 7.37 - 73.7 × 10(-5) mol L(-1) DXM, and the detection limit of the method is 1.29 × 10(-5) mol L(-1). The relative standard deviation (RSD) and relative error for six replicate measurements of 3.685 × 10(-4) mol L(-1) are 0.672 and 0.855%, respectively. The interference effect of some excepients has also been tested. The drug contents in pharmaceutical preparations were successfully determined by the proposed methods by applying the standard-addition technique.
本文描述了用于测定药物制剂中氢溴酸右美沙芬（DXM）的新型、简单且便捷的电位滴定法和分光光度法。电位滴定技术基于开发一种电位传感器，该传感器将右美沙芬四（对氯苯基）硼酸盐离子对络合物作为电活性物质，置于含有邻硝基苯基辛基醚或邻苯二甲酸二辛酯的增塑PVC基质膜中。该传感器在pH值为3.0 - 9.0的范围内，对浓度为1×10⁻⁵ - 1×10⁻² mol L⁻¹的右美沙芬呈现快速的近能斯特响应。检测限为2×10⁻⁶ mol L⁻¹ DXM，响应时间为瞬间（2秒）。所提出的分光光度法涉及DXM与铬黑T（EBT）反应形成离子缔合络合物。采用溶剂萃取来提高该方法的选择性。研究了最佳萃取和反应条件，并获得了该方法的分析特性。在7.37 - 73.7×10⁻⁵ mol L⁻¹ DXM范围内符合线性关系，该方法的检测限为1.29×10⁻⁵ mol L⁻¹。对3.685×10⁻⁴ mol L⁻¹进行六次重复测量的相对标准偏差（RSD）和相对误差分别为0.672%和0.855%。还测试了一些辅料的干扰效应。通过应用标准加入技术，所提出的方法成功测定了药物制剂中的药物含量。
