Rahman Nafisur, Anwar Nishat, Kashif Mohammad, Hoda Nasrul
Analytical Research Laboratory, Department of Chemistry, Aligarh Muslim University, Aligarh-202002, (U.P.) India.
Acta Pharm. 2006 Sep;56(3):347-57.
A simple and sensitive kinetic spectrophotometric method has been developed. The method is based on the reduction of Fe(III) with captopril. Fe(II) then reacts with potassium ferricyanide, resulting in the formation of a blue product. The reaction is followed spectrophotometrically by measuring the rate of change of absorbance at 730 nm. Thus, 1.23 x 10(-3) mol L(-1) FeCl3 and 3.04 x 10(-4) mol L(-1) potassium ferricyanide were used as optimum values for maximum concentration of captopril in the calibration graph. The initial rate is utilized for constructing the calibration graph, which was found to be linear in the range from 4.60 x 10(-6) to 5.06 x 10(-5) mol L(-1); detection limit is 1.99 x 10(-7) mol L(-1). The proposed method has been validated; the mean recovery ranges from 99.8 to 101.4% with RSD < 2%. Common excipients do not interfere with the determination. The point and interval hypotheses tests have been performed and confirmed that there is no significant difference between the proposed method and the conventional spectrophotometric method. The experimental true bias of all samples is lower than +/- 2%. The proposed method has been applied to the determination of captopril in bulk and dosage forms.
已开发出一种简单且灵敏的动力学分光光度法。该方法基于卡托普利对Fe(III)的还原。然后Fe(II)与铁氰化钾反应，生成蓝色产物。通过测量730 nm处吸光度的变化速率，用分光光度法跟踪该反应。因此，1.23×10(-3) mol L(-1) FeCl3和3.04×10(-4) mol L(-1)铁氰化钾被用作校准曲线中卡托普利最大浓度的最佳值。利用初始速率构建校准曲线，发现其在4.60×10(-6)至5.06×10(-5) mol L(-1)范围内呈线性；检测限为1.99×10(-7) mol L(-1)。所提出的方法已得到验证；平均回收率在99.8%至101.4%之间，相对标准偏差<2%。常见辅料不干扰测定。已进行点和区间假设检验，证实所提出的方法与传统分光光度法之间无显著差异。所有样品的实验真实偏差均低于±2%。所提出的方法已应用于原料药和制剂中卡托普利的测定。
