The fate of nitroguanidine in the rat

The metabolism and disposition of nitroguanidine (NG), a component of military propellants and munitions, were examined in the rat. Radiolabeled nitroguanidine [( 14C]NG) was administered orally at doses of 20 and 200 mg/kg and intravenously at a dose of 20 mg/kg. Regardless of the route of administration, the radiolabel was recovered quantitatively in the urine of all animals within 48 hr after dosing. Chromatographic analysis of the urine indicated that the [14C]NG was excreted unchanged; no radiolabel was found in the expired air, feces, or tissues of the treated animals. No sex differences were seen in the disposition of NG. The kinetics of [14C]NG in the blood of the dosed animals was followed. The elimination half-life of NG was on the order of 2 hr. The bioavailability of orally administered NG was 100%; the kinetics of NG in the blood was not dose dependent. Examination of tissues 1 hr after an oral dose of NG showed that NG was evenly distributed throughout the body. Nitroguanidine is a chemical of low toxicity (LD50 greater than 5 g/kg); it is quantitatively absorbed from the gastrointestinal tract, distributed throughout the body, and rapidly excreted in the urine.