Freeze-Drying of mRNA-LNPs Vaccines: A Review

The instability of mRNA vaccines presents significant challenges for their storage, transportation, and large-scale distribution, particularly in resource-limited countries. Recently, freeze-drying (lyophilization) has been considered as a promising approach for preserving mRNA vaccine efficacy. This formulation technique enhances the long-term stability of mRNA vaccines by converting them into a stable dry powder. The purpose of this review is to provide an overview of the current knowledge on the progress of freeze-drying techniques for mRNA vaccines, with emphasis on the associated challenges. This review highlights the factors influencing the stability of freeze-dried mRNA vaccines and provides a comprehensive overview of the formulation components, including excipients, buffers, and surfactants, as well as the process parameters and storage conditions that aim to improve stability and shelf-life. By providing these insights, this review supports the advancement of more robust, scalable, and efficient lyophilization protocols, ultimately addressing the stability limitations of mRNA vaccines and enhancing their global accessibility.