Alvarez-Lueje Alejandro, Pujol Sara, Núñez-Vergara Luis J, Squella Juan A
J AOAC Int. 2002 Nov-Dec;85(6):1247-52.
Lercanidipine in ethanol-0.04M Britton-Robinson buffer (20 + 80) gives an irreversible anodic response on a glassy carbon electrode in a broad pH range (2-12) that depends on pH. This signal can be attributed to oxidation of the 1,4-dihydropyridine ring to give the corresponding pyridine derivative. For analytical purposes, differential pulse voltammetry at pH 4 was selected. Under these conditions, good values of both within- and interday reproducibility were obtained, with coefficient of variation (CV) values of 1.56 and 1.70%, respectively, for 10 successive runs. For quantitation, the calibration curve method was used for lercanidipine concentrations ranging from 1 x 10(-5) to 1 x 10(-4) M. The detection and quantitation limits were 1.39 x 10(-5) and 1.49 x 10(-5), respectively. A liquid chromatographic method with electrochemical detection was used for comparison. The voltammetric method showed good selectivity with respect to both excipients and degradation products. The recovery study exhibited a CV of 0.94% and an average recovery of 98.3%, and it was not necessary to treat the sample before the analysis. The method was successfully applied to the individual tablet assay of lercanidipine in commercial tablets.
乐卡地平在乙醇 - 0.04M Britton - Robinson缓冲液（20 + 80）中，于玻碳电极上在较宽的pH范围（2 - 12）内呈现不可逆的阳极响应，该响应取决于pH值。此信号可归因于1,4 - 二氢吡啶环的氧化，生成相应的吡啶衍生物。出于分析目的，选择了pH 4条件下的差分脉冲伏安法。在这些条件下，获得了良好的日内和日间重现性，连续10次运行的变异系数（CV）值分别为1.56%和1.70%。对于定量分析，采用校准曲线法测定乐卡地平浓度范围为1×10⁻⁵至1×10⁻⁴ M。检测限和定量限分别为1.39×10⁻⁵和1.49×10⁻⁵。采用液相色谱 - 电化学检测法进行比较。伏安法对辅料和降解产物均显示出良好的选择性。回收率研究的CV为0.94%，平均回收率为98.3%，且分析前无需对样品进行处理。该方法成功应用于市售片剂中乐卡地平的单片含量测定。
