scholarly journals Photodegradation of the benzothiostrobin in solution and on soil and glass surface

2017 ◽  
Vol 76 (2) ◽  
pp. 364-372 ◽  
Author(s):  
Zihao Zhou ◽  
Yu Yang ◽  
Zhangyu Zheng ◽  
Minghua Wang
Keyword(s):  
Organic Solvent ◽  
Glass Surface ◽  
Influence Factors ◽  
Soil Surface ◽  
Ultra Performance Liquid Chromatography ◽  
Initial Concentration ◽  
Degradation Rates ◽  
Liquid Chromatography Tandem Mass ◽  
Photodegradation Products ◽  
Main Influence

The photolytic characteristics of benzothiostrobin were investigated in solution and on soil and glass surface. The main influence factors such as initial concentration, organic solvent and the aqueous environmental substances, including NO2–, NO3–, Fe2+, Fe3+, H2O2 and turbidity were investigated. Three photodegradation products of benzothiostrobin were identified by ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). The photodegradation rates of benzothiostrobin increased with decreasing initial concentration of benzothiostrobin. The degradation rates of benzothiostrobin in different organic solvent showed the following order: n-hexane > methanol > acetonitrile > acetone. The photodegradation of benzothiostrobin was promoted by Fe3+, NO2– and H2O2, and were inhibited by Fe2+ and turbidity. The presence of NO3– had no effect on photodegradation. Benzothiostrobin was photodegraded at a slower rate on soil surface and glass surface compared to its photolysis in aqueous solution. The presumed photodegradation pathway was proposed to be the cleavage of the thioether bond in benzothiostrobin.

scholarly journals Photodegradation of the H1 Antihistaminic Topical Drugs Emedastine, Epinastine, and Ketotifen and ROS Tests for Estimations of Their Potent Phototoxicity

Pharmaceutics ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 560
Author(s):  
Anna Gumieniczek ◽  
Anna Berecka-Rycerz ◽  
Urszula Hubicka ◽  
Paweł Żmudzki ◽  
Karolina Lejwoda ◽  
...  
Keyword(s):  
Liquid Chromatography ◽  
High Performance ◽  
Ultra Performance Liquid Chromatography ◽  
First Order ◽  
Ph Values ◽  
First Order Kinetics ◽  
Chromatography Tandem Mass Spectrometry ◽  
Liquid Chromatography Tandem Mass ◽  
Photodegradation Products ◽  
Antihistaminic Drugs

In this study, important H1 antihistaminic drugs, i.e., emedastine (EME), epinastine (EPI), and ketotifen (KET), were irradiated with UV/Vis light (300–800 nm) in solutions of different pH values. Next, they were analyzed by new high performance liquid chromatography (HPLC) methods, in order to estimate the percentage of degradation and respective kinetics. Subsequently, ultra-performance liquid chromatography tandem-mass spectrometry (UPLC-MS/MS) was used to identify their photodegradation products and to propose degradation pathways. In addition, the peroxidation of linoleic acid and generation of singlet oxygen (SO) and superoxide anion (SA) were examined, together with the molar extinction coefficient (MEC) evaluation, to estimate their phototoxic risk. The photodegradation of all EME, EPI, and KET followed pseudo first-order kinetics. At pH values of 7.0 and 10.0, EPI was shown to be rather stable. However, its photostability was lower at pH 3.0. EME was shown to be photolabile in the whole range of pH values. In turn, KET was shown to be moderately labile at pH 3.0 and 7.0. However, it degraded completely in the buffer of pH 10.0. As a result, several photodegradation products were separated and identified using the UPLC-MS/MS method. Finally, our ROS assays showed a potent phototoxic risk in the following drug order: EPI < EME < KET. All of these results may be helpful for manufacturing, storing, and applying these substantial drugs, especially in their ocular formulations.

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