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.