The anthelmintic activity of a novel organic arsenical, R7/45, upon Brugia pahangi in Meriones unguiculatus.

The new organic arsenical R7/45 is a rapidly acting and very potent anthelmintic against adult Brugia pahangi in jirds. Against adult worms implanted into the peritoneal cavity 5 subcutaneous (SC) injections at 2.5 mg/kg of R7/45 killed 100% of adult worms. A single dose SC of 20 mg/kg was 100% effective and 10 mg/kg 76% effective against adult worms. When jirds were autopsied at different times after treatment at 20 mg/kg SC 89% of worms were dead within three days. R7/45 was not active when given by stomach intubation. Pretreatment of jirds with R7/45 had no effect on adult worms subsequently implanted into jirds. R7/45 was highly active against third and fourth stage larvae of B. pahangi in jirds.

The antifilarial activity of a novel group of organic arsenicals upon Brugia pahangi.

Mel W is a second generation anionic organic arsenical which is filaricidal but has sporadic and unacceptable lethal side effects. Eight new cationic derivatives have now been synthesized in an attempt to avoid the side effects and have been examined for their effects upon adult Brugia pahangi in Meriones unguiculatus. They were all shown to be potent filaricides and the two best compounds, Mel Ga and Mel Cy, were at least 95% effective in killing adult B. pahangi at 5 X 3.13 mg/kg when injected subcutaneously.

Therapeutic field trial of a macro- and microfilaricidal agent in canine filariasis.

The discovery in 1973 of a synergistic effect of the arsenical compound F 151, a macrofilaricide, and the benzimidazole compound HOE 33258, a microfilaricide, led to the preparation of the reaction product of F 151 and HOE 33258 (in the proportion 1 mol to 2 mol, respectively), which was designated by the letter E. This compound E proved to be an effective macro- and microfilaricidal agent when administered subcutaneously in a single well-tolerated dose to dogs that were naturally infected with Dirofilaria immitis.