Amin Alaa S, El-Sheikh Ragaa, Zahran Faten, Gouda Ayman Abou El-fetouh
Chemistry Department, Faculty of Science, Benha University, Benha, Egypt.
Spectrochim Acta A Mol Biomol Spectrosc. 2007 Jul;67(3-4):1088-93. doi: 10.1016/j.saa.2006.09.027. Epub 2006 Sep 28.
A simple, accurate and highly sensitive spectrophotometric method is proposed for the rapid determination of pipazethate hydrochloride, dextromethorphan hydrobromide and drotaverine hydrochloride using chromotrope 2B (C2B) and chromotrope 2R (C2R). The method consists of extracting the formed ion-associates into chloroform in the case of pipazethate HCl and dextromethorphan HBr or into methylene chloride in the case of drotaverine HCl. The ion-associates exhibit absorption maxima at 528, 540 and 532 nm with C2B and at 526, 517 and 522 nm with C2R for pipazethate HCl, dextromethorphan HBr and drotaverine HCl, respectively. The calibration curves resulting from the measurements of absorbance-concentration relations (at the optimum reaction conditions) of the extracted ion-pairs are linear over the concentration range 4.36-52.32 microg mL(-1) for pipazethate, 3.7-48.15 microg mL(-1) for dextromethorphan and 4.34-60.76 microg mL(-1) for drotaverine, respectively. The effect of acidity, reagent concentration, time, solvent and stoichiometric ratio of the ion-associates were estimated. The molar absorptivity and Sandell sensitivity of the reaction products were calculated. Statistical treatment of the results reflects that the procedure is precise, accurate and easily applied for the determination of the drugs under investigation in pure form and in their pharmaceutical preparations.
提出了一种简单、准确且高灵敏度的分光光度法，用于使用变色酸2B（C2B）和变色酸2R（C2R）快速测定盐酸哌苯甲醇、氢溴酸右美沙芬和盐酸屈他维林。该方法包括在盐酸哌苯甲醇和氢溴酸右美沙芬的情况下将形成的离子缔合物萃取到氯仿中，或者在盐酸屈他维林的情况下萃取到二氯甲烷中。对于盐酸哌苯甲醇、氢溴酸右美沙芬和盐酸屈他维林，离子缔合物分别在与C2B反应时于528、540和532 nm处呈现吸收最大值，在与C2R反应时于526、517和522 nm处呈现吸收最大值。由萃取的离子对的吸光度 - 浓度关系（在最佳反应条件下）测量得到的校准曲线在浓度范围分别为4.36 - 52.32 μg mL⁻¹（盐酸哌苯甲醇）、3.7 - 48.15 μg mL⁻¹（氢溴酸右美沙芬）和4.34 - 60.76 μg mL⁻¹（盐酸屈他维林）时呈线性。评估了酸度、试剂浓度、时间、溶剂和离子缔合物的化学计量比的影响。计算了反应产物的摩尔吸光系数和桑德尔灵敏度。结果的统计处理表明该方法精确、准确且易于应用于测定所研究药物的纯品及其药物制剂。
