Birgit Mueller-Chorus, Ph.D.
Manager, TCS, Components Development
八月 05, 2021
To characterize the stability profile of a drug product, there is a focus on critical quality attributes (CQAs). For lyophilized drug products, one of the CQAs is “residual moisture content”. To maintain the optimal low moisture level over a lyophilized drug product’s shelf life, it is important to understand the properties and limitations of the primary containment system, i.e., the ability to restrict moisture ingress into the vial.
A first requirement for a primary containment system is proper fit of vial and elastomer stopper. This promotes container closure integrity, which is essential to preventing moisture ingress. A second requirement is suitable dryness of the stopper. Many stoppers are sterilized by autoclave/steam, which results in moisture absorption. Stoppers will not suitably dry during lyophilization. A separate, validated, drying step is needed, e.g., approximately 8 hours at 105oC. Note that over-drying is not acceptable, as degradation or alteration of the extractable and leachable profile may result. A third requirement is selection of the proper stopper, more specifically the proper elastomer formulation. Every formulation has a characteristic moisture vapor transmission rate (MVTR); one with a low value should be selected. For example, chlorobutyl rubber is 0.3 g/m2-day, as compared to natural rubber which is 9.0 g/m2-day.
*. Container and Reconstitution Systems for Lyophilized Drug Products. P. McAndrew, D. Hostetler, F. DeGrazio. Lyophilization of Pharmaceuticals and Biologicals (ISBN 978-1-4939-8927-0). K.R. Ward and P.Matejtschuk, Eds., Humana Press, 193-214 (2019)