Studies in enteric anthelmintics: activity profile of prodrug of a bisbenzimidazole [1]

The comparative anthelmintic activity of a possible prodrug, 2,2'-dicarbomethoxyamino-5,5'-dibenzimidazolyl methanol (2) with its parent compound 2,2'-dicarbomethoxyamino-5,5'-dibenzimidazolyl ketone (1) and the reference drug mebendazole (3a) is reported. At a dose of 25 mg/kg, compound 2 was 100% effective against Ancylostoma ceylanicum in hamsters. Compound 2 also exhibited a similar order of activity against Syphacia obvelata, Hymenolepis nana and H. diminuta at a dose of 100 mg/kg. The drug exhibited lethal effects against metamorphic forms of A. ceylanicum at a dose of 100 mg/kg. However the trichostrongylids, Nippostrongylus brasiliensis remained unaffected up to a dose of 250 mg/kg of 2. Both 1 and 3a exhibited inferior activity than 2 except against adult A. ceylanicum. The activity of 1 and 2 has been explained on the basis of their ability to resist systemic hydrolysis resulting in higher concentration of the active drug in biophase.