Studies on Some Biological Aspects of Dihydrostreptomycin.

The catalytic conversion of streptomycin to a dihydro compound was recently described and some of the biological characteristics of the latter were noted (Peck et al., 1946; Fried and Wintersteiner, 1947; Bartz et al., 1946). Peck and his coworkers (1946) reported that dihydrostreptomycin showed in vitro activity against Bacillus subtilis, and Bartz et al. (1946) also reported activity against B. subtilis as well as against some ten other species. In vivo studies by Peck et al. (1946) showed that approximately twice as much dihydrostreptomycin trihydrochloride as streptomycin trihydrochloride, calcium chloride double salt was required to protect 50 per cent of the mice against one lethal dose of Salmonella schottmiuleri. Dihydrostreptomycin is not inactivated by cysteine, hydroxylamine (Peck et al., 1946), semicarbazide (Fried and Wintersteiner, 1947; Bartz et al., 1946), nor by treatment with mild alkali (Peck et al., 1946; Fried and Wintersteiner, 1947; Bartz et al., 1946). Hence, it is relatively stable compared to streptomycin. The present paper deals with some comparative biological characteristics of streptomycin and dihydrostreptomycin. For the bacterial spectrum shown in table 1, streptomycin trihydrochloride prepared from the crystalline trihelianthate was used. The dihydrostreptomycin employed was made from this streptomycin preparation (Fried and Wintersteiner, 1947). In the remaining comparisons shown here (tables 2 and 3, and figure 1) a streptomycin sulfate preparation having an activity of ca. 400 units per mg and its corresponding dihydro compound were used.1