Antimalarial activity of new floxacrine-related acridinedione derivatives: studies on blood schizontocidal action of potential candidates against P. berghei in mice and P. falciparum in vivo and in vitro.

Deoxyfloxacrine derivatives (1-hydrazone: S 83 0083; 1-imine: S 84 7277) and floxacrine derivatives (10-methoxy-floxacrine: L 84 7667; 1-imine: L 84 7693) selected from a series of newly synthesized 3-aryl-7-chloro-3,4-dihydro-1,9(2H,10H)-acridinediones were evaluated for blood schizontocidal activities in mice infected with asexual stages of various drug-resistant lines of P. berghei and in New World monkeys infected with blood schizonts of different chloroquine-resistant strains of P. falciparum.

The action of salinomycin-Na and lasalocid-Na on chloroquine- and mepacrine-resistant line of Plasmodium berghei K 173-strain in Wistar rats.

Salinomycin-Na and lasalocid-Na, two ionophorous antibiotics known for their anticoccidial activity, exhibit in vivo blood schizontocidal action on the Plasmodium berghei Keyberg 173 RC/M line that has a high level of resistance to chloroquine and mepacrine. Salinomycin was found to have a greater effect than lasalocid on asexual stages of this line. Trophozoites and schizonts were no longer found after a single dose of 20 mg/kg or five doses of 1.

The activity of fexinidazole (HOE 239) against experimental infections with Trypanosoma cruzi, trichomonads and Entamoeba histolytica.

A new 5-nitroimidazole compound, 1-methyl-2-(4-methylthiophenoxymethyl)-5-nitroimidazole: fexinidazole, HOE 239, was found to be highly active against experimental infections with Trypanosoma cruzi, Tritrichomonas foetus, Trichomonas vaginalis and Entamoeba histolytica. It was slightly superior to benznidazole and nifurtimox in suppressing parasitaemia in mice infected with T. cruzi.

10-Hydroxy-3,4-dihydroacridine-1,9(2H,10H)-diones, a new group of malaricidal and coccidiostatic compounds.

2-Nitrobenzaldehydes and 1,3-cyclohexanediones condense in a mixture of hydrochloric acid and glacial acetic acid to 10-hydroxy-3,4-dihydroacridine-1,9(2H,10H)-diones. Many compounds of this group reveal a pronounced coccidiostatic and malaricidal effect in vivo even against drug-resistant malaria parasites. Synthesis and chemotherapeutic results as well as structure-activity relationships are described.

Action of p-(4-amidino-phenoxy)-benzaldehyde-p-amidino-phenylhydrazone dihydrochloride on Leishmania donovani infections in the golden hamster.

The chemotherapeutic effect of a new diamidine, HOE 668, the p-(4-amidino-phenoxy)-benzaldehyde-p-amidino-phenylhydrazone dihydrochloride, was compared with that of known anti-leishmanial drugs in golden hamsters infected with Leishmania donovani. The effect of HOE 668 against visceral leishmaniasis proved superior to that of pentamidine isethionate and the pentavalent antimonial drugs, sodium stibogluconate and N-methylglucamine antimoniate. However, HOE 668 can be used only experimentally because of its toxicity.

Survival of Aegyptianella pullorum, Anaplasma marginale and various parasitic protozoa following prolonged storage in liquid nitrogen.

Various protozoa species were examined using in vivo and in vitro methods to determine their ability to survive prolonged periods of storage in liquid nitrogen. The following protozoan species were successfully recovered after they had been cryopreserved for a period over 10 years: Trypanosoma lewisi, T. cruzi, T.

1,4-Bis-[1-methyl-5-nitroimidazolyl-(2-methyleneimino)]-piperazine, a new drug with marked activity against Entamoeba histolytica. Short communication.

1,4-Bis-[1-methyl-5-nitroimidazolyl-(2-methyleneimino)]-piperazine (HOE 316) administered orally produces an effect which is clearly superior to that of metronidazole against Entamoeba histolytica in the golden hamster and slightly inferior against Trichomonas fetus and T. vaginalis in the mouse. The acute tolerance of the compound is very good (LD 50% greater than 10 g/kg body weight).

Trypanocidal effect of diamidine 98/202 in experimental Trypanosoma rhodesiense infection of the stumptailed macaque (Macaca arctoides).

The trypanocidal effect of preparation 98/202, a 6-Amidino-2-(4'-amidinophenyl)-thionaphthene dilactate, was investigated in 4 stumptailed macaques (Macaca arctoides) infected with Trypanosoma rhodesiense (strain: Hamburg, 1962), of which 2 animals had been treated previously with diminazene and pentamidine, respectively. The curative treatment with preparation 98/202 was carried out in all cases in the late stage of infection; at the beginning of treatment 3 of the 4 animals had already shown malaise with distinct affection of the central nervous system. The individual dose was 5 mg/kg (base) and was given by deep intramuscular injection on 2, 3 or 4 consecutive days.