Tian Jingzhi, Rustum Abu
Merial Inc., Analytical R&D, 631 US Route 1 South, North Brunswick, NJ 08902, USA.
J Chromatogr Sci. 2018 Feb 1;56(2):131-138. doi: 10.1093/chromsci/bmx091.
Imidacloprid is used as an active pharmaceutical ingredient (API) in veterinary drugs to control fleas and ticks for dogs and cats. Here we are reporting for the first time a validated stability-indicating reversed-phase UPLC-UV method for the assay of imidacloprid and estimation of its related compounds. The stability-indicating capability of this method has been demonstrated by a forced degradation study. All related compounds including processing impurities, imidacloprid API and degradates from stressed samples were well separated from each other. Structures of major degradates from forced degradation study were elucidated through UPLC-MS/MS and key degradation pathways were proposed from the proposed chemical structures of major degradates. The UPLC-UV method is carried out using an HSS T3 column (C18, 2.1 × 30 mm, 1.8 μm particle size) maintained at 30°C with mobile phase A (0.05% v/v of phosphoric acid in water) and mobile phase B (methanol/acetonitrile 75/25 v/v). Analytes are separated by a gradient elution and detected at 270 nm. The UPLC method is green and fast with only 6.5 min run time and about 3.5 ml mobile phase consumption for each sample analysis. The UPLC-UV method was validated according to ICH guidelines.
吡虫啉用作兽药中的活性药物成分（API），用于控制犬猫身上的跳蚤和蜱虫。在此，我们首次报道了一种经过验证的稳定性指示反相超高效液相色谱-紫外（UPLC-UV）方法，用于测定吡虫啉及其相关化合物的含量。通过强制降解研究证明了该方法的稳定性指示能力。所有相关化合物，包括工艺杂质、吡虫啉API以及强制降解样品中的降解产物，都能很好地彼此分离。通过超高效液相色谱-串联质谱（UPLC-MS/MS）阐明了强制降解研究中主要降解产物的结构，并根据主要降解产物的化学结构推测出关键降解途径。UPLC-UV方法采用HSS T3色谱柱（C18，2.1×30 mm，粒径1.8μm），柱温保持在30°C，流动相A为（水中0.05% v/v的磷酸），流动相B为（甲醇/乙腈75/25 v/v）。分析物通过梯度洗脱进行分离，并在270 nm处检测。该UPLC方法绿色且快速，每次样品分析的运行时间仅为6.5分钟，流动相消耗量约为3.5 ml。该UPLC-UV方法已按照国际协调会议（ICH）指南进行了验证。
