[Activity of intermittently administered rifampicin and cyclopentyl rifamycin (or DL473) on experimental tuberculosis in the mouse].

The results of recent experiences with experimental tuberculous chemotherapy in the mouse give information on the activity of rifampicin (RMP) administered intermittently and on the activity of Cyclopentyl-Rifampicin (or DL473). The activity of RMP decreases as one spaces the treatment without increasing the dose. These observations are compatible with the known facts concerning the mechanism of action of RMP on RNA polymerase, and are unfavourable as regards the intermittent administration of RMP. Cyclopentyl-Rifampicin, a new derivative of Rifamycine SV, administered once per week, is as active as RMP administered six days per week, both in the initial as well as the continuation phase of treatment.