CHEMOTHERAPY OF TRYPANOSOME AND SPIROCHETE INFECTIONS : BIOLOGICAL SERIES. II. THE THERAPEUTIC ACTION OF...

N-PhenyIglycineamide-p-arsonic acid is an agent of marked therapeutic action in the treatment of experimental trypanosomiasis of mice, rats, and guinea pigs. It possesses an average curative range of from 0.2 to 0.3 gm. per kilo of body weight of the sodium salt against a 24 hour infection in mice and rats produced by several species of pathogenic trypanosomes. Since the lethal dose for mice is from 2 to 2.25 gm. and for rats 0.75 gm. per kilo of body weight, we have curative ratios of 1:8 and 1:3 respectively. The curative dose for guinea pigs is 0.15 gm. per kilo of body weight, thus giving a curative ratio of 1:10. The trypanocidal activity of this compound is relatively rapid in all three animal species, for the peripheral blood is cleared of organisms within 24 hours after its administration, and in addition, the lower limits of the curative range are comparatively sharply defined. Intraperitoneal, intravenous, and subcutaneous routes of administration for all practical purposes may be considered equally efficacious in Tr. brucei infections of mice both as regards the speed of action of the drug and the average curative range. The administration of the drug in therapeutic amounts in all three animal species is not followed by manifestations of organic or functional injury, but, on the contrary, the genera] physical condition of the treated animals shows an immediate and continued marked improvement. The therapeutic activity in trypanosomiasis of mice, rats, and guinea pigs as evidenced by the relative speed and sharpness of action, together with the curative ratio as expressed in fractions of the minimum lethal dose, and the absence of organic injury or functional disturbance following therapeutic doses are significant and characteristic features of the amide of N-phenylglycine-p-arsonic acid.