Effect in vitro of metabolites of praziouantel on schistosoma japonicum

The metabolites of prazi-quantel were studied in urine of patients infested with Schistosoma japonicum and healthy rats. The patients were given oral-ly praziquantel 30 mg/kg/d x2 d and the metabolites in urine were isolated by non-ionic resin extraction techniques. Crys-tal-l thus obtained was subjected to UV-visible absorption, IR and mass spectrum analysis. The chemical structure of crys-tal-l appears as follows. In rats, after po [14C]pra_ziquantel, 6 metabolites (ui-uo) were isolated from the urine by TLC and radioautography. Among these metabolites, crystal-l, u3, u4, and u6 showed various degrees of antischistosomal activity in vitro, but less active than praziquantel.