Heba Mohamed, Ramadan Nesrin, El-Laithy Moustafa
Cairo University, Faculty of Pharmacy, Analytical Chemistry, Kasr Al-Ainy 11652, Cairo, Egypt.
J AOAC Int. 2008 Nov-Dec;91(6):1318-30.
Four polyvinyl chloride (PVC) matrix membrane electrodes responsive to 2 drugs affecting the urogenital system--oxybutynin hydrochloride (OX) and flavoxate hydrochloride (FX)--were developed, described, and characterized. A precipitation-based technique with tungstophosphate (TP) and ammonium reineckate (R) anions as electroactive materials in a PVC matrix with an OX cation was used for electrode 1 and 2 fabrication, respectively. Electrode 3 and 4 fabrication was based on use of the precipitation technique of FX cation with tetrakis (4-chlorophenyl) borate and R anions as electroactive materials. Fast and stable Nernstian responses in the range 1 x 10(-2)-1 x 10(-6) M for the 2 drugs over the pH range 5-8 revealed the performance characteristics of these electrodes, which were evaluated according to International Union of Pure and Applied Chemistry recommendations. The method was applied to FX and OX in their pharmaceutical formulations and in human plasma samples. The 4 proposed sensors were found to be specific for the drugs in the presence of up to 60% of their degradation products. Validation of the method according to the quality assurance standards showed suitability of the proposed electrodes for use in the quality control assessment of these drugs. The recoveries for determination of the drugs by the 4 proposed selective electrodes were 99.5 +/- 0.5, 100.0 +/- 0.4, 99.9 +/- 0.4, and 100.1 +/- 0.4% for sensors 1-4, respectively. Statistical comparison between the results obtained by this method and the official method of the drugs was done, and no significant difference found.
研制、描述并表征了四种对影响泌尿生殖系统的两种药物——盐酸奥昔布宁（OX）和盐酸黄酮哌酯（FX）有响应的聚氯乙烯（PVC）基质膜电极。分别采用基于沉淀的技术，以钨磷酸盐（TP）和雷氏铵盐（R）阴离子作为电活性材料，在含有OX阳离子的PVC基质中制备电极1和2。电极3和4的制备基于FX阳离子与四（4 - 氯苯基）硼酸盐和R阴离子作为电活性材料的沉淀技术。在pH值5 - 8范围内，这两种药物在1×10⁻² - 1×10⁻⁶ M浓度范围内呈现快速且稳定的能斯特响应，揭示了这些电极的性能特征，这些特征是根据国际纯粹与应用化学联合会的建议进行评估的。该方法应用于FX和OX的药物制剂以及人体血浆样本中。发现所提出的4种传感器在存在高达60%的降解产物时对药物具有特异性。根据质量保证标准对该方法进行验证，结果表明所提出的电极适用于这些药物的质量控制评估。所提出的4种选择性电极测定药物的回收率分别为：传感器1为99.5±0.5%，传感器2为100.0±0.4%，传感器3为99.9±0.4%，传感器4为100.1±0.4%。对该方法所得结果与药物官方方法所得结果进行了统计比较，未发现显著差异。
