Inhibition of multiplication of leprosy bacilli in nude mice by intermittent dosed new rifamycin derivative krm-1648 combined with sparfloxacin

The inhibition of multiplication of mycobacterium leprae inoculated into footpads of nude mice by the oral administration of new rifamycin derivative KRM-1648 and a new quinolone, sparfloxacin [SPFX]; was examined. When these two drugs were administered alternately at intervals of 3 or 4 days [thus once weekly for each drug] between 3 and 5 months after infection, the use of 0.6 mg/kg of KRM-1648 and 10mg/kg of sparfloxacin were found to be sufficient to prevent entirely multiplication of M.leprae. However with the alternate administration of 0.3 kg of KRM-1648 and 5 mg/kg sparfloxacin the inhibition of multiplication of M.leprae was partial as it was also examined with the administration of 1 mg/kg of KRM-1648 alone or 20 mg/kg/ of sparfloxacin alone once a weekly. However the simultaneous administration of 0.6 mg/kg of KRM-1648 with 10 mg/kg of sparfloxacin once per week entirely prevented the multiplication of M. leprae. Taking these findings into consideration there is possible future use of these type multi drug regimens was discussed