Charles University, Faculty of Science, Department of Analytical Chemistry, Hlavova 8/2030, 128 43 Prague 2, Czech Republic.
Charles University, Faculty of Science, Department of Analytical Chemistry, Hlavova 8/2030, 128 43 Prague 2, Czech Republic.
J Pharm Biomed Anal. 2022 Jan 5;207:114341. doi: 10.1016/j.jpba.2021.114341. Epub 2021 Aug 24.
This paper highlights the potential of electrochemical flow cells for oxidative-stress testing of active pharmaceutical ingredients using canagliflozin as a model substance. Based on design of experiments, we developed our method through a reduced combinatorial design, optimizing the following independent variables: cell size, electrolyte flow rate, electrolyte concentration, and electrolyte pH. Using ammonium phosphate buffer with methanol in a 50/50 vol ratio as a working electrolyte, we electrochemically oxidized samples and analyzed them by high-performance liquid chromatography, considering the following dependent variables: peak area of each impurity, peak area of canagliflozin, and the percentage of the corresponding peak areas. Our results showed that the most significant independent variables were electrolyte pH and flow rate. By data optimization, we determined the most suitable conditions for electrochemical oxidation of canagliflozin, namely 50 µm cell size, 300 mM electrolyte concentration, 0.1 mL/h electrolyte flow rate, and electrolyte pH = 4. The repeatability of the method, expressed as the relative standard deviation of the canagliflozin peak area, measured in ten separately oxidized samples, was 1.64%. For comparison purposes, we performed a degradation experiment using hydrogen peroxide, identifying five identical impurities in both cases, as confirmed by mass spectrometry. The degradation products formed when using the chemical method after 1, 3, and 7 days totaled 0.09%, 0.75%, and 3.75%, respectively, and the degradation products formed when using the electrochemical method after 3 h totaled 3.11%. Oxidation with hydrogen peroxide required 7 days, whereas electrochemical oxidation was completed in 3 h. Overall, the electrochemical method significantly saves time and reduces the consumption of active ingredients and solvents thanks to the miniaturized size of the electrochemical cell, thereby minimizing the costs of forced degradation studies.
本文重点介绍了电化学流动池在使用坎格列净作为模型药物进行药物活性成分氧化应激测试方面的潜力。通过实验设计，我们采用简化组合设计开发了该方法，优化了以下独立变量：电池尺寸、电解质流速、电解质浓度和电解质 pH。使用 50/50（体积比）的甲醇/磷酸铵缓冲液作为工作电解质，我们对样品进行电化学氧化，并通过高效液相色谱法进行分析，考虑以下因变量：每个杂质的峰面积、坎格列净的峰面积以及相应峰面积的百分比。我们的结果表明，最显著的独立变量是电解质 pH 值和流速。通过数据优化，我们确定了电化学氧化坎格列净的最适宜条件，即 50µm 电池尺寸、300mM 电解质浓度、0.1mL/h 电解质流速和 pH=4。通过在十个单独氧化的样品中测量，该方法的重复性（表示为坎格列净峰面积的相对标准偏差）为 1.64%。为了进行比较，我们使用过氧化氢进行了降解实验，通过质谱法确认了两种情况下存在五种相同的杂质。使用化学方法在 1、3 和 7 天分别形成的降解产物分别为 0.09%、0.75%和 3.75%，而使用电化学方法在 3 小时后形成的降解产物为 3.11%。使用过氧化氢氧化需要 7 天，而电化学氧化在 3 小时内完成。总体而言，由于电化学池的小型化，电化学方法显著节省了时间，并减少了活性成分和溶剂的消耗，从而最大限度地降低了强制降解研究的成本。
