The prediction of hydrolysis and biodegradation of Novichoks using in silico toxicology methods

Novichoks constitute a relatively new class of nerve agents of extreme toxicity that we have had the opportunity to ex-perience three times already. After the first case (Salisbury, UK), a public debate about Novichoks began, which re-sulted in the realisation of the nature of these chemicals. From a social security point of view, examining their properties, especially toxicological and environmental aspects, are crucial. After the CWC (Chemical Warfare Agent) list update, the candidate structures for the Novichoks may be over 10,000 compounds. It would be extremely labori-ous to conduct experimental research for each. Understanding their environmental persistence and health hazards is an essential national issue. Moreover, due to the high risk posed by contact with hazardous Novichok substances, in silico research was applied to estimate hydrolysis and biodegradation safely. The present study elucidates, using QSAR models, the environmental fate of the Novichoks studied (n = 17). The results indicate that Novichoks released into the environment hydrolyse at various rates, from extremely fast (<1 day) to very slow (more than a year). Further-more, ultimate biodegradation from weeks to months is expected for most compounds, which classifies them as rela-tively difficult biodegradable. Applying reliable in silico methods (QSAR Toolbox and EPI Suite) for predicting various parameters is crucial to prepare for the upcoming usage of Novichoks.