Estimation of Stability of lyophilized BCG Vaccine for Use as an In-Country Reference Standard Vaccine

Abstract

National control laboratory is necessary to prepare vaccine reference standard in order to quality control potency values in the country. Therefore, to prepare and use BCG vaccine for long that will be beneficial to continually lot-release control of BCG vaccine produced in the country. In the experiment, BCG vaccine in liquid form obtained from manufacturer was distributed into vials and prepared in a freeze-dried in laboratory and controlled the quality of necessary parameters, including estimation of stability of vaccine. It was found that lyophilized BCG vaccines showed good physical characteristics with moisture residue of 0.86%, potency values within an acceptable range (2 - 26 x 10⁶ cfu/ml) reconstitution time approximately 100 second without difference of pH values between before and after freeze dried (pH 6.93 and pH 6.97) as well as no contamination of fungi, bacteria and mycoplasma. When estimation of stability test at temperature -70 °C for long term storage, lyophilized BCG vaccines were still potent till 2 years. It was shown that vaccines were stable, not deteriorated at -70 °C during the study. When vaccine exposed at stress conditions, the result also indicated that BCG vaccines were stable at -20°C and 4 °C for longer than 16 weeks and temperature at 20 °C for longer than 8 weeks, while it was deteriorated at 37 °C after 4 weeks. However, exposure at higher temperature (45 °C for 1 week) led to deterioration of potency because of a percentage of culturable particles less than 20%. However, from this study it can be confirmed that estimation of stability for lyophilized BCG vaccines remain potent for 2 years, it indicates that it can be potent enough for being as an in-country reference standard vaccine.