EchothiophateIodide

General Description

Echothiophate iodide,(2-mercaptoethyl)trimethylammonium iodide, S-ester withO,O-diethylphosphorothioate (Phospholine Iodide), occursas a white, crystalline, hygroscopic solid that has aslight mercaptan-like odor. It is soluble in water (1:1) anddehydrated alcohol (1:25); aqueous solutions have a pH ofabout 4 and are stable at room temperature for about1 month.
Echothiophate iodide is a long-lasting cholinesterase inhibitorof the irreversible type, as is isofluorphate. Unlikethe latter, however, it is a quaternary salt, and when appliedlocally, its distribution in tissues is limited, which can bevery desirable. It is used as a long-acting anticholinesteraseagent in the treatment of glaucoma.