The preservation of viability of BCG vaccine freeze-dried in a new extracellular protector, evaluated by ATP-dependent bioluminescence assay

A new protective medium CP-94 (a combination of sodium glutamate and sorbit ol), with cryoprotective properties and supposed to have the capacity to co unteract the osmotic shock during the rehydration stage, was used in an att empt to preserve the long term viability of the freeze-dried BCG vaccine. C ell viability was estimated both by the classical colony forming units (CFU ) method and the bioluminescence assay used for measuring the content of ad enosine triphosphate (ATP), a more rapid and sensitive method. The CP-94 protective medium allowed preserving the cell viability level of the BCG vaccine at 80-90% of the initial value. This medium enhances the qu ality of the Romanian BCG vaccine as it facilitates preservation of the num ber of viable writs per dose as well as the extension of the long-term stab ility to two years.