engleski

The photolytic degradation of hydroxychloroquine in the environment and the identification of its degradation products

It is important to know the environmental fate of hydroxychloroquine (HCQ) since it is a high production volume pharmaceutical product which has a potential for being persistent and bioaccumulative. In this work photolytic degradation of hydroxychloroquine in the environment was investigated and its degradation products were identified. Additionaly, toxicity toward marine bacterium Vibrio fischeri was monitored during photodegradation. The photolytic degradation of HCQ was investigated under simulated solar radiation (300 − 800 nm) in MilliQ water and spring water. Degradation was slow with half- lives of 5.5 h and 11.6 h in spring and MilliQ water, respectively. Significant influence of pH value (4, 7 and 9) on the photodegradation rate was observed, i.e. degradation was faster at higher pH value. Obtained half-lives ranged from 5.5 min for pH = 9 to 23.1 h for pH = 4 . Photodegradation followed first order kinetics with coefficients of determination (r2) higher than 0.99. The identification and proposed structures of the degradation products formed during photolytic degradation of hydroxychloroquine were performed by HPLC coupled with MS/MS. The m/z values, isotope peaks and fragmentation patterns obtained for the degradation products through HPLC- (ESI)MS/MS studies helped to propose the structures of degradation compounds. Several different degradation products are identified as a photolysis products of hydroxychloroquine. The primary identified degradation product at all pH values was desethylhydroxychloroquine (m/z = 308) which is also found as metabolite in the human body. The main fragmentation pathways are the losses of alkyl groups attached to the nitrogen atoms. Observed increase in the inhibition toward Vibrio fischeri implies that toxicity is higher for the solution of the degradation products than for hydroxychloroquine. These studies are carried out to establish the importance of photolytic processes of hydroxychloroquine in the environment.

pharmaceutical ; hydroxychloroquine ; photolytic degradation ; degradation products ; environment

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