Dimethylmorpholinophosphoramidate (DMMPA) Persistence in Various Tissues of the Rat

The persistence of dimethylmorpholinophosphoramidate (DMMPA) in various tissues of the rat was examined in order to assess whether it could pose a threat to chronically exposed animals. The material was purified by filtration through alumina in ether followed by fractional distillation. Significant amounts of DMMPA were found in the liver, kidneys and brain of rats 4 hours after i.p. injection, but only traces were recovered at 48 hours after injection. Recovery of DMMPA in the urine over 48 hours was approximately 60%, and almost all of this was excreted in the first 24 hours. DMMPA had no effect on a rat phrenic nerve-diaphragm preparation, nor on the guinea pig right atrium. DMMPA is unlikely to present a chronic threat to the exposed animal or human.