Cyclosarin-An Organophosphate Nerve Agent

Organophosphorus compounds ascribed to as nerve agents (sarin, soman, tabun, cyclosarin) are highly toxic, and are considered to be the most dangerous chemical compounds. All apparently share a common mechanism of cholinesterase inhibition and can cause similar svmotoms. The . . standard therapy, in the case of organophosphorus poisoning, has the prophylactic use of reversibly acting AChE inhibitors and antidotal administration of AChE reactivators-oximes. Unfortunately, none of these oximes can be regarded as a broad spectrum antidote, ie, effective against all nerve agents. While the presently available oximes (pralidoxime, ohidoxime) are not considered to be sufficiently effective against nerve agents, especially in the case of soman poisoning, the H oximes (HI-6, HLo7) appear to,be very promising antidotes against nerve agents because these are able to protect the experimental animals from toxic effects and improve survival of animals poisoned with supralethal doses. A lot of research has been pursued on the treatment of sarin, soman, and tabun, but cyclosarin was not considered for such a study for a long time. Recently, attention of researchers has also turned to cyclosarin because of its potential use as a chemical warfare agent. Cyclosarin is highly toxic organophosphorus compound which is resistant to conventional oxime therapy. This paper reviews the latest positionof cyclosarin in standpoint of medical treatment by various reactivators considering the ability of various oximes, HI-6, HS-6, BI-6, and KO33 of their reactivation potency.