A comparison of the reactivating and therapeutic efficacy of newly developed oximes (K347, K628) with commonly used oximes (obidoxime, HI-6) against tabun in rats and mice

Abstract

The potency of newly developed reactivators of nerve agent–inhibited acetylcholinesterase (K347, K628) in reactivating tabun-inhibited acetylcholinesterase and reducing tabun-induced lethal toxic effects was compared with currently available oximes (obidoxime, the oxime HI-6), using in vivo methods. Studies that determined the percentage of reactivation of tabun-inhibited blood and tissue acetycholinesterase in poisoned rats showed that the reactivating efficacy of both newly developed oximes is comparable with the oxime HI-6, but it is significantly lower than the reactivating effects of obidoxime. The monopyridinium oxime, K347, was also found to be able to reduce lethal toxic effects in tabun-poisoned mice, while the therapeutic efficacy of another newly developed bispyridinium oxime, K628, was negligible. The therapeutic efficacy of K347 was higher than the potency of the oxime, HI-6, but it was lower than the therapeutic effects of obidoxime. Thus, the reactivating and therapeutic potency of both newly developed oximes (K347, K628) was not more effective then currently available oximes, and therefore, they are not suitable for the replacement of commonly used oximes (especially obidoxime) for the treatment of acute tabun poisoning.