Abstract The photodegradation of pranoprofen (PP), which is a member of the 2-arylpropionic acid family of non-steroidal anti-inflammatory drugs, in aqueous media under ultraviolet light (UV) irradiation was studied herein. Our purpose is to clarify the photostability and photochemical behavior of PP. The photodegradation of PP and the generation of its photoproducts were monitored by means of high-performance liquid chromatography (HPLC). PP was degraded completely after 2 h of UV irradiation with the generation of several photoproducts identified in HPLC analysis. The chemical structures of nine PP photoproducts were elucidated based on the mass/charge ratio (m/z) values and fragmentation patterns of protonated ions obtained from electrospray ionization liquid chromatography mass spectrometry (ESI-LC/MS/MS). Among these nine PP photoproducts, the main product was 7-acetyl-5H-[1]benzopyrano[2,3-b]pyridin-5-one, which was the final oxidized form of PP. The photodegradation pathways are proposed, showing that oxidation of excited PP might be an initial process. This is the first study showing the photochemical behavior of PP, and these results allow further research focused on the photostability of PP in commercial tablets and its changed formulation, the toxicological potencies of photoproducts and photostabilization approaches. Graphical Abstract Highlights The photodegradation of pranoprofen and the generation of its photoproducts by UV irradiation were examined. HPLC and ESI-LC/MS/MS were utilized as analytical tools for achieving this purpose. Pranoprofen was degraded completely after UV irradiation for 2 h with the generation of several photoproducts. Up to nine photoproducts were detected, and their structures were proposed by examining UV absorption and MS spectral profiles. The photodegradation pathways in aqueous media were proposed.

中文翻译：

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水介质中紫外光照射诱导普拉洛芬光降解的评价

摘要 本文研究了非甾体类抗炎药 2-芳基丙酸家族的成员普拉洛芬 (PP) 在紫外光 (UV) 照射下在水性介质中的光降解。我们的目的是阐明 PP 的光稳定性和光化学行为。PP 的光降解及其光产物的产生通过高效液相色谱 (HPLC) 进行监测。PP 在紫外线照射 2 小时后完全降解，并产生了几种在 HPLC 分析中鉴定的光产物。基于质荷比 (m/z) 值和从电喷雾电离液相色谱质谱 (ESI-LC/MS/MS) 获得的质子化离子的碎片模式，阐明了九种 PP 光产品的化学结构。这九款PP写真产品中，主要产物是7-乙酰-5H-[1]苯并吡喃[2,3-b]吡啶-5-one，它是PP的最终氧化形式。提出了光降解途径，表明激发的 PP 的氧化可能是一个初始过程。这是第一项展示 PP 光化学行为的研究，这些结果允许进一步研究 PP 在商业片剂中的光稳定性及其改变的配方、光产物的毒理学效力和光稳定方法。图形摘要亮点研究了普拉洛芬的光降解及其通过紫外线照射产生的光产物。HPLC 和 ESI-LC/MS/MS 被用作实现此目的的分析工具。在紫外线照射 2 小时后，普拉洛芬完全降解，产生几种光产物。检测到多达九种光产物，并通过检查 UV 吸收和 MS 光谱图提出了它们的结构。提出了水介质中的光降解途径。