RationaleLomefloxacin hydrochloride ear drops are highly unstable to light and prone to produce photodegradation impurities. These impurities might be related to the phototoxicity of lomefloxacin, which could seriously threaten the health of patients. In this article, the photodegradation impurity profile in lomefloxacin hydrochloride ear drops was studied for further improvement of quality control of the drug.MethodsBy studying the chromatographic behavior of photodegradation impurities, the photodegradation impurities in lomefloxacin hydrochloride ear drops were separated and detected effectively. Liquid chromatography combined with ion trap/time‐of‐flight mass spectrometry was applied to characterize the structures of the photodegradation impurities in lomefloxacin hydrochloride ear drops.ResultsThe structures of 17 impurities in lomefloxacin hydrochloride ear drops were elucidated based on high‐resolution MSn data in positive ion mode, 12 of them being unknown impurities.ConclusionsThe structural characteristics and fragmentation patterns of the photodegradation impurities were also studied. The study of the photodegradation impurity profile in lomefloxacin hydrochloride ear drops provides a scientific basis for quality control of these ear drops and ensures the safety of drug use by the public.

中文翻译：

---

液相色谱结合离子阱/飞行时间质谱法研究盐酸洛美沙星滴耳剂光降解杂质谱

基本原理盐酸洛美沙星滴耳剂对光高度不稳定，容易产生光降解杂质。这些杂质可能与洛美沙星的光毒性有关，严重威胁患者的健康。本文对盐酸洛美沙星滴耳剂中的光降解杂质谱进行研究，以进一步提高药物的质量控制。方法通过研究光降解杂质的色谱行为，对盐酸洛美沙星滴耳剂中的光降解杂质进行有效分离和检测。采用液相色谱结合离子阱/飞行时间质谱法对盐酸洛美沙星滴耳液中光降解杂质的结构进行表征。结果基于高分辨质谱阐明了盐酸洛美沙星滴耳液中17种杂质的结构。n正离子模式数据，其中12个为未知杂质。结论还研究了光降解杂质的结构特征和碎裂模式。对盐酸洛美沙星滴耳剂光降解杂质谱的研究，为该滴耳剂的质量控制提供了科学依据，保证了公众用药安全。