Among these compounds the acetylated derivative of 4-amino-2-morpholino-1,3,5-triazine, which can reduce the intensity of pulmonary lesions in mice infected by influenza viruses type B, without affecting, however, the replication of these agents in fertile eggs, appeared to be of particular interest because of its low toxicity (oral LD50 in the rat = 3.48 g/kg; 95% fiducial limits, 2.67 to 4.55). A detailed study of its metabolism was made, therefore, in laboratory animals to ascertain the rate of absorption and the amount of the compound which can be found, after oral administration, in the blood and in various organs (alimentary tract, liver, kidneys) and to investigate the forms in which the compound is present in the organism, that is its metabolites, the possibility of accumulation in the organs, and the rate and the degree of excretion by different routes.
METHODSRadioactive 4-acetamido-2-morpholino-1,3,5-triazine and 4-amino-2-morpholino-1,3,5-triazine were obtained by labelling the triazine ring with 14C at position 6.
METABOLISM OF TRIAZINE DERIVATIVES4-acetamido-2-morpholino-1,3,5-triazine (R=CO.CH,) was prepared by N-acetylation. The two substances each had a specific activity of 38 ftc/mM.In the experiments on the metabolism of 4-acetamido-2-morpholino-1,3,5-triazine, male Swiss albino mice weighing 15 g were used. For each of the experiments indicated below, three groups of five mice were fasted for 15 hr and kept in individual metabolism cages for the whole experimental period. The animals used for periods longer than 12 hr were fed the usual laboratory diet. Each animal was given, by stomach tube, 22.1 jM of the labelled compound (0.84 pc) suspended in 0.2 ml. of a 10% aqueous solution of gum arabic.Measurements of radioactivity were made on the carbon dioxide expired in the first 24 hr after the administration of 4-acetamido-2-morpholino-1,3,5-triazine and on samples of blood taken during ether anaesthesia, by section of a carotid artery, at different periods from the beginning of the experiment (from 15 min up to 24 hr). Urinary and faecal radioactivity was measured on samples collected in the periods 0 to 24 and 0 to 48 hr. The radioactivity in the kidneys and in the liver was measured in animals killed at different intervals, from 24 to 240 hr after the administration of the compound, while the radioactivity in the tissues of the stomach and of the small intestine, freed of the materials contained in their lumen by washing with 0.9% saline, was determined in the first hours (from 1 to 6) after the administration.The measurements of radioactivity in the expired carbon dioxide, urine and faeces were carried out on combined samples from fifteen animals, while the determinations of radioactivity in the blood, kidneys, liver, stomach and small intestine were done on three distinct samples, each corresponding to five animals.The organic materials in the samples were converted to precipitates of barium carbonate by homogenization and wet oxidation according to Rabinowitz (1957). All the samples of ...