The potency of three newly developed bispyridinium compounds (K454, K456, K458) to reactivate
tabun-inhibited
acetylcholinesterase and reduce
tabun-induced lethal toxic effects was compared with the
oxime K203 and
trimedoxime using in vivo methods. The study determining percentage of reactivation of
tabun-inhibited diaphragm and brain
acetylcholinesterase in poisoned rats showed that the reactivating efficacy of all newly developed
oximes is comparable with K203 but lower than the reactivating potency of
trimedoxime in diaphragm. In the brain, their potency to reactivate
tabun-inhibited
acetylcholinesterase is lower compared with
trimedoxime and the
oxime K203. All three newly developed
oximes were also found to be relatively effective in reducing lethal toxic effects in
tabun-poisoned mice. Their therapeutic efficacy is consistent with the therapeutic potency of the
oxime K203. On the other hand, their potency to reduce acute toxicity of
tabun is significantly lower compared with
trimedoxime. In conclusion, the reactivating and therapeutic potency of all three newly developed
oximes does not prevail the effectiveness of the
oxime K203 and
trimedoxime and, therefore, they are not suitable for their replacement of commonly used
oximes for the treatment of acute
tabun poisoning.