A comparison of the efficacy of a bispyridinium oxime--1,4-bis-(2-hydroxyiminomethylpyridinium) butane dibromide and currently used oximes to reactivate sarin, tabun or cyclosarin-inhibited acetylcholinesterase by in vitro methods.

The efficacy of a bispyridinium oxime 1,4-bis(2-hydroxyiminomethylpyridinium) butane dibromide, called K033, and of currently used oximes (pralidoxime, obidoxime, oxime HI-6), to reactivate acetylcholinesterase inhibited by various nerve agents (sarin, tabun cyclosarin) was tested by in vitro methods. The new oxime K033 was found to be a more efficacious reactivator of sarin or cyclosarin-inhibited acetylcholinesterase than pralidoxime and obidoxime but it did not reach the efficacy of oxime HI-6 in the case of the inhibition of acetylcholinesterase by sarin or cyclosarin. On the other hand, oxime K033 was more efficacious than oxime HI-6 in reactivating tabun-inhibited acetylcholinesterase. Thus, oxime K033 seems to be a relatively efficacious broad spectrum acetylcholinesterase reactivator and, therefore, could be useful if no information about the type of nerve agent used was available.