El-Shiekh Ragaa, Amin Alaa S, Zahran Faten, Gouda Ayman A
Zagazig University, Faculty of Science, Chemistry Department, Zagazig, Egypt.
J AOAC Int. 2007 May-Jun;90(3):686-92.
Three simple, sensitive, and reproducible spectrophotometric methods (A-C) for the determination of pipazethate hydrochloride (PiCl) in pure form and in pharmaceutical formulations are described. The first and second methods, A and B, are based on the oxidation of the drug by Fe3+ in the presence of o-phenanthroline (o-phen) or bipyridyl (bipy). The formation of tris-complex upon reactions with Fe3+-o-phen and/or Fe3+-bipy mixture in an acetate buffer solution of the optimum pH values was demonstrated at 510 and 522 nm, respectively, with o-phen and bipy. The third method, C, is based on the reduction of Fe(III) by PiCl in acid medium and subsequent interaction of Fe(II) with ferricyanide to form Prussian blue, which exhibits an absorption maximum at 750 nm. The concentration ranges are from 0.5 to 8, 2 to 16, and 3 to 15 microg/mL for Methods A-C, respectively. For more accurate analysis, Ringbom optimum concentration ranges were calculated. The molar absorptivity, Sandell sensitivity, and detection and quantitation limits were calculated. The developed methods were successfully applied to the determination of PiCl in bulk and pharmaceutical formulations without any interference from common excipients. The relative standard deviations were < or =0.83% with recoveries of 98.9-101.15%.
本文描述了三种简单、灵敏且可重现的分光光度法（方法A - C），用于测定纯品及药物制剂中的盐酸哌嗪乙胺（PiCl）。第一种和第二种方法，即方法A和方法B，是基于在邻菲啰啉（邻菲）或联吡啶（联 bipy）存在下，Fe3 + 对药物的氧化作用。在最佳pH值的醋酸盐缓冲溶液中，分别与Fe3 + -邻菲和/或Fe3 + -联吡啶混合物反应形成的三元络合物，在510 nm和522 nm处有吸收，分别对应邻菲和联吡啶。第三种方法，即方法C，是基于在酸性介质中PiCl对Fe(III)的还原作用，以及随后Fe(II)与铁氰化物相互作用形成普鲁士蓝，其在750 nm处有最大吸收。方法A - C的浓度范围分别为0.5至8、2至16和3至15 μg/mL。为了进行更准确的分析，计算了林邦最佳浓度范围。计算了摩尔吸光率、桑德尔灵敏度以及检测限和定量限。所建立的方法成功应用于原料药和药物制剂中PiCl的测定，不受常见辅料的干扰。相对标准偏差≤0.83%，回收率为98.9 - 101.15%。
