Takamura K, Kusu F, Abdel-Wadood H, El-Rabbat N, Saleh G, Refaat I
School of Pharmacy, Tokyo University of Pharmacy and Life Science, 1432-1 Horinouchi, Hachioji, Tokyo 192-03, Japan.
Biomed Chromatogr. 2000 Nov;14(7):453-8. doi: 10.1002/1099-0801(200011)14:7<453::AID-BMC5>3.0.CO;2-7.
The electrochemical behaviour of isradipine in a mixed solution of Britton-Robinson buffer (pH 11.8):acetonitrile:methanol (6:3:1, v/v) was studied by cyclic voltammetry and spectroelectrochemistry using an optically transparent thin layer electrode of carbon cloth. The cyclic voltammogram showed several peaks whose shape and potentials depended on the pH. The peak at 330 nm, corresponding to the absorbance of the dihydropyridine ring, disappeared after electrolysis at a potential that was more positive than the oxidation peak. The oxidation peak corresponds to the oxidation of the dihydropyridine ring. Peak height at pH 11.8 was proportional to isradipine concentration. On the basis of the redox properties of isradipine, HPLC was conducted applying electrochemical detection on a polybutadiene coated alumina column using an alkaline mobile phase. The method was applied for the determination of isradipine content in human serum. A good linear relationship between isradipine concentration and peak height was found in the concentration range of 2-200 ng/mL with a correlation coefficient of 0.9924. The detection limit was 0.5 ng/mL. The within-day and day-to-day variation were examined for control human serum and percentage relative standard deviation ranged from 0.5 to 6.7. Interference from many other coadministered drugs was studied in the specified experimental conditions. Photo and heat stabilities of the compound were also studied.
采用碳布光学透明薄层电极，通过循环伏安法和光谱电化学法研究了伊拉地平在 Britton-Robinson 缓冲液（pH 11.8）：乙腈：甲醇（6:3:1，v/v）混合溶液中的电化学行为。循环伏安图显示出几个峰，其形状和电位取决于 pH 值。对应于二氢吡啶环吸光度的 330 nm 处的峰，在比氧化峰更正的电位下电解后消失。氧化峰对应于二氢吡啶环的氧化。pH 11.8 时的峰高与伊拉地平浓度成正比。基于伊拉地平的氧化还原性质，在聚丁二烯涂覆的氧化铝柱上采用电化学检测，以碱性流动相进行高效液相色谱分析。该方法用于测定人血清中伊拉地平的含量。在 2 - 200 ng/mL 的浓度范围内，伊拉地平浓度与峰高之间呈现良好的线性关系，相关系数为 0.9924。检测限为 0.5 ng/mL。对对照人血清进行日内和日间变化检测，相对标准偏差百分比范围为 0.5%至 6.7%。在特定实验条件下研究了许多其他合用药物的干扰情况。还研究了该化合物的光稳定性和热稳定性。
