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

บทคัดย่อ

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 OC for long term storage, lyophilized BCG vaccines
were still potent till 2 years. It was shown that vaccines were stable, not deteriorated at -70 OC during
the study. When vaccine exposed at stress conditions, the result also indicated that BCG vaccines were
stable at -20OC and 4 OC for longer than 16 weeks and temperature at 20 OC for longer than 8 weeks,
while it was deteriorated at 37 OC after 4 weeks. However, exposure at higher temperature (45 OC 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.
Key words: BCG, BCG reference standard, freeze-dried, stability