Photodegradation is widely known as a changer of both the quality and the quantity of several chemical compounds. In this study, we sought to examine the photochemical behavior of triprolidine (TRP), which is a member of the first-generation antihistamine and utilized for a relief of an allergic conditions, in an aqueous media. There are no reports focused on its potential photoproducts and photodegradation pathways in detail to the best of our knowledge. TRP photodegradation induced by ultraviolet light (UV) irradiation was monitored utilizing high-performance liquid chromatography (HPLC), and structural elucidation of the TRP photoproduct was performed by electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS) and nuclear magnetic resonance (NMR). Finally, the mechanism of TRP photodegradation was speculated based on the identified photoproduct. TRP was photodegraded dependent on the irradiation time of UV in proportion to the generation of one TRP photoproduct (TRP-P). Structural determination by LC-ESI-MS/MS and NMR clarified that TRP-P was the geometrical isomer of TRP, which was formed by the cis-trans conversion of double bond. UV irradiation experiment for TRP-P revealed the conversion from it to TRP. It is clarified that cis-trans conversion between TRP and TRP-P is photo-equilibrium reaction and TRP-P is predominant under the condition as this experiment. Toxicological potencies of TRP and TRP-P might not be observed by ProTox-II in silico toxicity evaluation. This is the first study evaluating the photochemical behavior of TRP.

中文翻译：

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抗组胺药曲普立啶在水介质中光化学行为的评价。

众所周知，光降解可以改变多种化合物的质量和数量。在这项研究中，我们试图研究曲普立啶 (TRP) 在水介质中的光化学行为，它是第一代抗组胺药的成员，用于缓解过敏症状。据我们所知，还没有详细报道其潜在的光产物和光降解途径。利用高效液相色谱 (HPLC) 监测紫外线 (UV) 照射引起的 TRP 光降解，并通过电喷雾电离串联质谱 (LC-ESI-MS/MS) 和核磁共振对 TRP 光产物进行结构解析（核磁共振）。最后，根据鉴定的光产物推测了TRP光降解的机理。TRP 的光降解取决于紫外线的照射时间，与一种 TRP 光产物 (TRP-P) 的生成成比例。LC-ESI-MS/MS和NMR结构测定表明，TRP-P是TRP的几何异构体，由双键顺反转化而成。TRP-P 的紫外线照射实验揭示了从 TRP-P 到 TRP 的转化。说明本实验条件下TRP与TRP-P之间的顺反转化是光平衡反应，且TRP-P占主导地位。在计算机毒性评估中，ProTox-II 可能无法观察到 TRP 和 TRP-P 的毒理学效力。这是第一个评估 TRP 光化学行为的研究。