The Reactivating and Therapeutic Efficacy of Oximes to Counteract Russian VX Poisonings

Abstract

Russian VX (O-isobutyl-S-(2-diethylaminoethyl)methylphosphonothioate) is the structural analogue of VX agent. It differs from VX agent (O-ethyl-S-(2-diisopropylaminoethyl) methylphosphonothioate) by two alkyl groups. The potency of currently available oximes (pralidoxime, obidoxime, HI-6) to reactivate Russian VX-inhibited acetylcholinesterase and to eliminate Russian VX-induced acute toxic effects was evaluated using in vivo methods. In vivo determined percentage of reactivation of Russian VX-inhibited blood and brain acetylcholinesterase in poisoned rats shows that HI-6 seems to be the most efficacious reactivator of Russian VX-inhibited acetylcholinesterase among currently used oximes in the peripheral compartment, whereas no difference between reactivating efficacy of all tested oximes was observed in the central compartment. The oxime HI-6 was also found to be the most efficacious oxime in the elimination of acute lethal toxic effects in Russian VX-poisoned mice among all studied oximes. Thus, the oxime HI-6 seems to be the most suitable oxime for the antidotal treatment of acute poisonings with Russian VX as in the case of VX, sarin, cyclosarin, and soman poisonings.