Spectrophotometric determination of pipazethate HCl, dextromethorphan HBr and drotaverine HCl in their pharmaceutical preparations

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• 作者：Alaa S. Amin ; Ragaa El-Sheikh ; Faten Zahran ; Ayman Abou El-fetouh Gouda
• 关键词：Spectrophotometry ; Pipazethate HCl ; Dextromethorphan HBr ; Drotaverine HCl ; Chromotrope 2B ; Chromotrope 2R ; Extraction ; Pharmaceutical preparations
• 刊名：Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy
• 出版年：2007
• 出版时间：July 2007
• 年：2007
• 卷：67
• 期：3-4
• 页码：1088-1093
• 全文大小：249 K

文摘

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 μg mL⁻¹ for pipazethate, 3.7–48.15 μg mL⁻¹ for dextromethorphan and 4.34–60.76 μg 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.