Salmonella typhi Ty21a의 동결 건조와 안정성

The lyophilization and stability of Salmonella typhi Ty21a

Salmonella typhi Ty21a is an attenuated strain of S. typhimurium and used for oral typhoid vaccine. In an attempt to increase the stability of Ty2la manufacturing typhoid vaccine, we studied about the stability of freeze-dried Ty2la including additives at various temperature conditions. In order to investigate the freeze-drying rate of Ty21a according to various absorbance, we lyophilized Ty2la by using 8% sucrose as a stabilizer. The optimal freeze-drying rate of Ty21a was appeared when OD (optical density) value of the growth was between 2.5 and 3.0. To investigate the stability of Ty2la at various temperature, the viability was measured after storaging the freeze-dried Ty21a at the room temperature, cold and freezing condition for I week. The viability of Ty21a in cold and freezing storage condition was 5 times more stable than in room temperature. To search the most stable additives for the freeze-dried Ty21a, the viability of Ty21a including additives at the various storage condition was estimated. Mannitol and lactose were the most stable additives. Theses results suggest that the OD value of Ty21a growth, low temperature, mannitol and lactose are important factors for the optimal freeze-drying rate, the stable storage and the most stable additives, respectively.