Chloroquine, 7-chloro-4-(4-diethylamino-1-methylbutylamino) quinoline, one of the 4-aminoquinoline series of compounds studied during the war time antimalarial drug research program, has proven to be a non-toxic agent with a high degree of suppressive antiplasmodial activity (1). Its activity against human amebiasis was described in 1948 as being good in hepatic infection and poor in intestinal infections (2). This has been confirmed (3, 4, 5, 6, 7) and extended to include good results in pleural infections (8). Sontoquine, 3-methyl-7-chloro-4-(4-diethylamino-1-methylbutylamino) quinoline is another 4-aminoquinoline derivative with comparable antimalarial activity (9). The diphosphate salt of chloroquine, the salt employed in amebiasis, and the bisulfate salt of sontoquine are absorbed from the intestinal tract to approximately 90 per cent with subsequent fecal excretion of about 10 per cent of the oral dose, whereas the naphthoate salt of sontoquine is absorbed only to about 80 per cent as a result of which the fecal concentration is approximately doubled.
Present Address: Department of Internal Medicine, American University of Beirut, Beirut, Lebanon.