New potentiometric sensitive and selective modified carbon paste (MCPE) electrodes based on ion pair formation between phosphotungestic acid (PTA), sodium tetraphenyl borate (NaTPB), phosphomolybdic acid (PMA) or ammonium reineckate (RN) and oxybutynin hydrochloride (Ox.HCl) has been developed. The proposed electrodes have Nernstian slope values of 58.50±0.71, 58.71±1.20, 54.80±1.30 and 59.20±0.70 mV decade⁻¹ for electrodes modified with 20, 10, 5 and 10 mg of Ox-TPB (electrode I), Ox-RN (electrode II), Ox-PMA (electrode III) and Ox-PTA (electrode IV) ion pairs, respectively. It is found that the dynamic drug concentration range at 25 °C is 1.0×10⁻⁵–1.0×10⁻² mol L⁻¹. The response of MCPEs is pH independent in the range 2.0–6.0 with a fast response time of 10 s for electrode I and 12 s for electrodes II-IV. These electrodes have good Nernstian response in the temperature range 10–60 °C with slope (isothermal coefficient) equal 0.791×10⁻³, 0.769×10⁻³, 0.629×10⁻³ and 1.277×10⁻³ V/°C for electrodes I, II , III and IV respectively. These small values indicate the high thermal stability of the electrodes. The MCPEs have shown a relatively long life time of 36 days. A pure and pharmaceutical formulation of Ox.HCl has quantified using calibration and standard addition methods and the obtained results agreed with that of the official HPLC method. Validation parameters have been optimized according to ICH recommendations. Limits of detection and quantification are calculated under the optimized conditions. For the analytical applications, pharmaceutical dose form has performed. Various interferents have been used to investigate the interference in the analytical application and found that the proposed method would be well adopted for real sample analysis.

中文翻译：

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修饰碳糊电极上电位法测定药物中盐酸奥昔布宁的含量

新的电位敏感和选择性修饰碳糊（MCPE）电极，基于磷酸磷酸（PTA），四苯基硼酸钠（NaTPB），磷钼酸（PMA）或reineckate铵（RN）和盐酸奥昔宁（Ox.HCl）之间的离子对形成已经被开发出来。所提出的电极具有能斯特的斜率值58.50±0.71，58.71±1.20，54.80±1.30 59.20和±0.70毫伏十年^-1与20，10，5和10毫克的Ox-TPB（电极I），OX-的修饰电极RN（电极II），Ox-PMA（电极III）和Ox-PTA（电极IV）离子对。发现在25℃下的动态药物浓度范围为1.0×10 ^-5 –1.0×10 ^-2 mol L ^-1。MCPE的响应在2.0-6.0范围内与pH无关，电极I的响应时间为10 s，电极II-IV的响应时间为12 s。这些电极具有在温度范围10-60好能斯特响应°的斜率（等温系数）C等于0.791×10 ^-3，0.769×10 ^-3，0.629×10 ^-3和1.277×10 ^-3分别为电极I，II，III和IV的V /°C。这些小的值表明电极的高热稳定性。MCPE的使用寿命相对较长，为36天。使用校准和标准添加方法对纯净的药用盐酸制剂进行了定量，所得结果与官方HPLC方法一致。验证参数已根据ICH建议进行了优化。在优化条件下计算检出限和定量限。对于分析应用，已经执行了药物剂型。各种干扰物已被用于研究分析应用中的干扰，并发现所提出的方法将很适合实际样品分析。