Evaluation on stability process of Brucella melitensis - Rev. 1 vaccine in Iran



According to the reports of WHO, stability of Rev.1 vaccine should take more than one year, while the expiring date for the vaccine produced in Iran is 3 to 4 months, therefore any attempt to elongate the stability of this vaccine can solve many problems of the production including the request of Veterinary Organization of Iran in this regard. The objective of this study was to increase the stability of this vaccine using various preserving materials in lyophilisation process. Nine effective preserving materials in two different volumes and different lyophilisation procedures were examined .We found that the best preserving materials which are added to the base formula for Rev.1 vaccine is consisted of bactocasitone %2.5, sucrose %5, L-glutamic acid sodium salt %1. As a result we formulate the most suitable compound in terms of bacterial mass after lyophilisation. The other factor which had to be improved was the duration of liquid form of the vaccine before lyophilisation process which causes reduction of the organism %50 to %70 per dose of the vaccine. This problem was solved by reduction of liquid phase. The most important practical result of this research was finding the optimum condition for the dose of the Rev.1 vaccine as 1-4×109 CFU and 0.5- 3× 106 CFU for the Reduced dose with 1-2% humidity and the vacuum of 1-2×10-3. In these conditions the vaccine can be kept and used for more than 8 months. Hence the expiring date of the present vaccines under these conditions would be increased up to eight months.