A-series agent A-234 belongs to a new generation of nerve agents. The poisoning of a former Russian spy Sergei Skripal and his daughter in Salisbury, England, in March 2018 led to the inclusion of A-234 and other A-series agents into the Chemical Weapons Convention. Even though five years have already passed, there is still very little information on its chemical properties, biological activities, and treatment options with established antidotes. In this article, we first assessed A-234 stability in neutral pH for subsequent experiments. Then, we determined its inhibitory potential towards human recombinant acetylcholinesterase (HssAChE; EC 3.1.1.7) and butyrylcholinesterase (HssBChE; EC 3.1.1.8), the ability of HI-6, obidoxime, pralidoxime, methoxime, and trimedoxime to reactivate inhibited cholinesterases (ChEs), its toxicity in rats and therapeutic effects of different antidotal approaches. Finally, we utilized molecular dynamics to explain our findings. The results of spontaneous A-234 hydrolysis showed a slow process with a reaction rate displaying a triphasic course during the first 72 h (the residual concentration 86.2%). A-234 was found to be a potent inhibitor of both human ChEs (HssAChE IC50 = 0.101 ± 0.003 µM and HssBChE IC50 = 0.036 ± 0.002 µM), whereas the five marketed oximes have negligible reactivation ability toward A-234-inhibited HssAChE and HssBChE. The acute toxicity of A-234 is comparable to that of VX and in the context of therapy, atropine and diazepam effectively mitigate A-234 lethality. Even though oxime administration may induce minor improvements, selected oximes (HI-6 and methoxime) do not reactivate ChEs in vivo. Molecular dynamics implies that all marketed oximes are weak nucleophiles, which may explain the failure to reactivate the A-234 phosphorus-serine oxygen bond characterized by low partial charge, in particular, HI-6 and trimedoxime oxime oxygen may not be able to effectively approach the A-234 phosphorus, while pralidoxime displayed low interaction energy. This study is the first to provide essential experimental preclinical data on the A-234 compound.

• Klíčová slova
• Acute toxicity, Hydrolysis, Nerve agent A-234, Reactivation, Therapy,
• MeSH
• acetylcholinesterasa MeSH
• antidota farmakologie   MeSH
• butyrylcholinesterasa MeSH
• cholinesterasové inhibitory toxicita   MeSH
• fosfor MeSH
• krysa rodu Rattus MeSH
• kyslík MeSH
• lidé MeSH
• oximy farmakologie   MeSH
• pralidoximové sloučeniny * MeSH
• pyridinové sloučeniny farmakologie   MeSH
• reaktivátory cholinesterasy * farmakologie   MeSH
• taurin analogy a deriváty   MeSH
• trimedoxim farmakologie   MeSH
• zvířata MeSH
• Check Tag
• krysa rodu Rattus MeSH
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• 2-(N-cyclohexylamino)ethanesulfonic acid MeSH Prohlížeč
• acetylcholinesterasa MeSH
• antidota MeSH
• asoxime chloride MeSH Prohlížeč
• butyrylcholinesterasa MeSH
• cholinesterasové inhibitory MeSH
• fosfor MeSH
• kyslík MeSH
• N,N'-monomethylenebis(pyridiniumaldoxime) MeSH Prohlížeč
• oximy MeSH
• pralidoxime MeSH Prohlížeč
• pralidoximové sloučeniny * MeSH
• pyridinové sloučeniny MeSH
• reaktivátory cholinesterasy * MeSH
• taurin MeSH
• trimedoxim MeSH

"Novichok" refers to a new group of nerve agents called the A-series agents. Their existence came to light in 2018 after incidents in the UK and again in 2020 in Russia. They are unique organophosphorus-based compounds developed during the Cold War in a program called Foliant in the USSR. This review is based on original chemical entities from Mirzayanov's memoirs published in 2008. Due to classified research, a considerable debate arose about their structures, and hence, various structural moieties were speculated. For this reason, the scientific literature is highly incomplete and, in some cases, contradictory. This review critically assesses the information published to date on this class of compounds. The scope of this work is to summarize all the available and relevant information, including the physicochemical properties, chemical synthesis, mechanism of action, toxicity, pharmacokinetics, and medical countermeasures used to date. The environmental stability of A-series agents, the lack of environmentally safe decontamination, their high toxicity, and the scarcity of information on post-contamination treatment pose a challenge for managing possible incidents.

• Klíčová slova
• A-series agents, Analysis, Environmental stability, Physicochemical properties, Therapy, Toxicity,
• MeSH
• kontaminace léku * MeSH
• nervová bojová látka * toxicita   MeSH
• organofosforové sloučeniny MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH
• Názvy látek
• nervová bojová látka * MeSH
• organofosforové sloučeniny MeSH

Certain AChE reactivators, asoxime, obidoxime, K027, K048, and K075, when taken in overdoses and sometimes even when introduced within therapeutic ranges, may injure the different organs. As a continuation of previously published data, in this study, Wistar rats have sacrificed 24 hrs and 7 days after single im application of 0.1LD50, 0.5LD50 and 1.0LD50 of each reactivator, and examinated tissue samples were obtained for pathohistological and semiquantitative analysis. A severity of tissue alteration, expressed as different tissue damage scores were evaluated. Morphological structure of examinated tissues treated with of 0.1LD50 of all reactivators was comparable with the control group of rats. Moderate injuries were seen in visceral tissues treated with 0.5LD50 of asoxime, obidoxime and K027. Acute damages were enlarged after treatment with 0.5LD50 and 1.0LD50 of all reactivators during the next 7 days. The most prominent changes were seen in rats treated with 1.0LD50 of K048 and K075 (P < 0.001 vs. control and asoxime-treated group). All reactivators given by a single, high, unitary dose regimen, have an adverse effect not only on the main visceral tissue, but on the whole rat as well, but the exact mechanism of cellular injury remains to be confirmed in further investigation.

• MeSH
• biopsie MeSH
• chemické bojové látky škodlivé účinky   chemie   toxicita   MeSH
• histocytochemie MeSH
• krysa rodu Rattus MeSH
• LD50 MeSH
• molekulární struktura MeSH
• orgánová specificita MeSH
• oximy aplikace a dávkování   škodlivé účinky   chemie   toxicita   MeSH
• plíce účinky léků   metabolismus   patologie   MeSH
• vnitřnosti účinky léků   patologie   MeSH
• vztah mezi dávkou a účinkem léčiva MeSH
• žaludek účinky léků   patologie   MeSH
• zvířata MeSH
• Check Tag
• krysa rodu Rattus MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• chemické bojové látky MeSH
• oximy MeSH

Therapeutic application of newly developed oximes is limited due to their adverse effects on different tissues. Within this article, it has been investigated which morphological changes could be observed in Wistar rats after the treatment with increasing doses of selected acetyl cholinesterase reactivators - asoxime, obidoxime, K027, K048, and K075. Subsequently, heart, diaphragm and musculus popliteus were obtained for pathohistological and semiquantitative analysis 24 hrs and 7 days after im administration of a single dose of 0.1 LD50, 0.5 LD50, and 1.0 LD50 of each oxime. Different muscle damage score was based on an estimation scale from 0 (no damage) to 5 (strong damage). In rats treated with 0.1 LD50 of each oxime, muscle fibres did not show any change. The intensive degeneration was found in all muscles after treatment with 0.5 LD50 of asoxime and obidoxime, respectively. Acute toxic muscle injury was developed within 7 days following treatment with 0.5 LD50 and 1.0 LD50 of each oxime, with the highest values in K048 and K075 group (P < 0.001 vs. control and asoxime), respectively. The early muscle alterations observed in our study seem to contribute to the pathogenesis of the oxime-induced toxic muscle injury, which probably manifests as necrosis and/or inflammation.

• MeSH
• bránice účinky léků   zranění   MeSH
• kosterní svaly účinky léků   zranění   MeSH
• krysa rodu Rattus MeSH
• myozitida chemicky indukované   MeSH
• nekróza MeSH
• oximy toxicita   MeSH
• potkani Wistar MeSH
• pyridinové sloučeniny toxicita   MeSH
• srdce účinky léků   MeSH
• svaly účinky léků   patologie   MeSH
• testy akutní toxicity MeSH
• vztah mezi dávkou a účinkem léčiva MeSH
• zvířata MeSH
• Check Tag
• krysa rodu Rattus MeSH
• mužské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• 1-(4-hydroxyiminomethylpyridinium)-3-(carbamoylpyridinium) propane dibromide MeSH Prohlížeč
• 1-(4-hydroxyiminomethylpyridinium)-4-(4-carbamoylpyridinium)butane MeSH Prohlížeč
• K075 compound MeSH Prohlížeč
• oximy MeSH
• pyridinové sloučeniny MeSH