Pharmacokinetics and pharmacodynamics of chlorine dioxide

Abstract

Chlorine dioxide (ClO2) is widely used as a drinking water disinfectant in many countries. Due to its antibiotic and antiviral capacity, it has aroused interest as a potential therapeutic agent with respect to the COVID-19 disease, AIDS and Influenza. As a result of this debate in scientific and governmental settings, it was deemed highly timely to provide an up-to-date assessment of the pharmacokinetics and pharmacodynamics of ClO2. The main findings indicate that, due to its high chemical reactivity, ClO2 is rapidly reduced in oral and gastric secretions, producing chlorite (ClO2⁻), which becomes the active agent responsible for its systemic actions. ClO2 also showed potential to act as an oxidant or antioxidant depending on the concentration. Of particular therapeutic interest are the findings that, at low concentrations, ClO2⁻ can protect erythrocytes from oxidative stress while inhibiting excessive production of hypochlorous acid (HClO) mediated by myeloperoxidase (MPO), thus reversing the inflammatory responses and macrophage activation. Finally, taurine-chloramine represents the most relevant functional product formed under the influence of ClO2⁻, said molecule activates the erythroid nuclear factor 2 (Nrf2), (this transcription factor regulates the inducible expression of numerous genes for detoxifying and antioxidant enzymes) , increases the expression of heme-oxygenase (HO-1), protects cells from death caused by hydrogen peroxide (H2O2), improves the expression and activities of antioxidant enzymes, such as superoxide dismutase, catalase and glutathione peroxidase, and contributes to the resolution of the inflammatory process.