Freeze-drying of live oral streptomycin-dependent mutant Shigella vaccines: survival of streptomycin-dependent Shigella flexneri 2a after freeze-drying

Although the relatively successful freeze-drying of streptomycin-dependent mutant Shigella vaccines has been reported previously, further studies have been undertaken for the following reasons: (1) To improve the survival rate of the vaccine strains after freeze-drying. (2) To see whether monosodium glutamate can be eliminated as a stabilizer as it is reported to produce pharmacological effects in man.