Stability of collapse lyophilized influenza vaccine formulations

A clear limitation of many liquid vaccines is the obligatory cold-chain distribution system. Therefore, distribution of a dried vaccine formulation may be beneficial in terms of vaccine stability, handling and transport. Collapse freeze-drying is a process which utilizes fairly aggressive but at the same time economic lyophilization cycles where the formulation is dried above its glass transition temperature.In this study, we used collapse freeze-drying for a thermosensitive model influenza vaccine (Pandemrix®). The dried lyophilizates were further cryo-milled to engineer powder particles in the size range of approximately 20–80 μm which is applicable for epidermal powder immunization.Vaccine potency and stability were neither affected by high temperature input during collapse lyophilization nor over a storage period of six months. Furthermore, cryo-milled vaccine lyophilizates showed good storage stability of up to three months at high storage temperature (40 °C).This technique can provide a powerful tool for the worldwide distribution of vaccine and for new application technologies such as engineered powder immunization.

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