Freeze-drying: A flourishing strategy to fabricate stable pharmaceutical and biological products

Freeze-drying (FD) of nanoparticles, microorganisms, genes, and vaccines is an auspicious technique used to enhance long-term stability and facilitate transportation mainly for products that require specific conditions like cold chains. Although freeze-drying is considered a delicate drying process, it can cause numerous stresses that induce chemical and physical instabilities. Subsequently, the inclusion of suitable excipients along with optimizing the process parameters is crucial to attain stable lyophilizates with high-quality attributes. The current review highlights the state of the art of the freeze-drying process applications in nanoparticulate systems, microorganisms, genes, and vaccine formulations. Moreover, the work focuses on the different stresses facing these systems during FD cycle and the strategies which are utilized for their stabilizations during lyophilization and storage.