Nucleoside structure promotes the degradation of antiviral drugs in simulated sunlight-activated periodate system

Since the outbreak of Corona Virus Disease 2019, the widespread utilization of antiviral drugs with nucleoside and non-nucleoside structures has inevitably posed environmental risks. However, there is a lack of comprehensive research on whether nucleoside structures have an impact on their degradation behavior in aquatic environments. This study established a simulated sunlight-activated periodate (SSL/PI) system to effectively degrade zidovudine (ZDV), used as a model pollutant representative of antiviral drugs. Results showed that 1 O 2 and O 2 ∙− were identified as the main reactive species responsible for ZDV degradation. The primary degradation pathways involved C-N bond cleavage, dehydrogenation, and the disruption of azide group. The SSL/PI system demonstrated selective oxidation capabilities, with nucleoside analogue antiviral drugs (NAADs) faster than non-nucleoside antiviral drugs (NNADs). It was found that NAADs with low octanol/water partition coefficient and polarizability values are more susceptible to oxidation and removal compared to NNADs. This may be attributed to the higher hydrophilicity, reduced molecular aggregation, and resistance to deformation of NAADs compared to NNADs, thereby accelerating the oxidation process. Overall, this study offers new insights into the selective oxidative mechanisms of SSL/PI for antiviral drugs and the crucial role of nucleoside structures in the removal process.