Efficacy of praziquantel and Ro 15-5458, a 9-acridanone-hydrazone derivative, against Schistosoma haematobium.

The efficacy of Ro 15-5458 ([10-(2-diethylamino)ethyl)-9-acridanone(thiazolidin-2-ylidene)hydrazone, CAS 92928-47-7) as a new antischistosomal drug was studied in hamsters using a dose of 20 mg/kg body weight against an Egyptian strain of Schistosoma haematobium, in comparison with praziquantel (PZQ, CAS 55268-74-1) (full dose 1000 mg/kg body weight). This was carried out at 4, 8 and 12 weeks post cercarial exposure of hamsters. The criteria used for the assessment of drug efficacy were the worm load, oogram pattern and number of ova/g liver and intestine. Results revealed that in earlier stages of infection (4 weeks post cercarial exposure), Ro 15-5458 proved to be more effective than PZO, the worm load was reduced by 83.2% and 55.6% from the untreated control group, respectively. At the same time, treatment with Ro 15-5458 increased the ratio of dead ova, while treatment with PZQ showed no change in the oogram pattern compared with the untreated control group. The reduction of eggs/g liver and intestine was higher in the group treated with Ro 15-5458, being 95.7% and 98.2%, compared to 65.3% and 79.2% in the PZQ group, respectively. However, in older infection (at 8 and 12 weeks post cercarial exposure) both drugs produced similar positive results regarding worm load, oogram pattern and the number of eggs/g liver and intestinal tissues. Consequently, Ro 15-5458 proved to be as efficient a drug as PZQ in the treatment of mature infection of schistosomiasis haematobium. Furthermore it showed much better effect in immature cases of infection.