A Comparison of the Neuroprotective Efficacy of Newly Developed Oximes (K156, K203) and Currently Available Oximes (Obidoxime, HI-6) in Cyclosarin-poisoned Rats

The neuroprotective effects of newly developed oximes (K156, K203) and currently available oximes (obidoxime, HI-6) in combination with atropine in rats poisoned with cyclosarin were studied. The cyclosarin-induced neurotoxicity was monitored using a functional observational battery 24 hours after cyclosarin challenge. The results indicate that a newly developed oxime K156 is able to counteract slightly cyclosarin-induced neurotoxicity while another newly developed oxime K203 is completely ineffective in reducing cyclosarin-induced neurotoxic signs and symptoms. The neuroprotective efficacy of K156 is comparable with commonly used obidoxime and oxime HI-6. Thus, none of the newly developed oximes achieves better neuroprotective efficacy than both commonly used oximes. They are therefore not suitable replacements for antidotal treatment of acute poisonings with cyclosarin.