Light-assisted drying (LAD) for anhydrous preservation of biologics: processing of samples inside glass lyophilization vials

Protein-based therapeutics are used to treat or prevent a range of diseases, but a challenge for the expanded use of these products is the need for cold storage that makes distribution difficult in low-resource settings. Lyophilization is a common method used to stabilize protein-based products. However, this process remains expensive, and many freeze-dried proteins require cold-chain storage. Anhydrous preservation in an amorphous trehalose matrix has been successfully used as an alternative to lyophilization. A new processing technique called light assisted drying (LAD) has been used to successfully dry proteins in preparation for anhydrous storage. Water is selectively heated via near-infrared (1064 nm) illumination, rapidly removing water from a sample, and forming an amorphous matrix that can be stored at supra-zero temperatures. In previous work, large volume samples (0.25 ml) were successfully LAD processed on glass coverslips, but this substrate is not typically used in industry. In this study, large volume samples are LAD processed in vials that are commonly used to lyophilize vaccines. After LAD processing, the samples are stored at room temperature (20.C) or refrigerated (4.C) for one month. The end moisture content of samples was determined immediately after processing/storage to evaluate the effectiveness of water removal via LAD. The trehalose matrix was characterized using polarized light imaging to determine if crystallization occurred during storage, potentially damaging embedded proteins. These preliminary studies indicate that LAD can effectively stabilize large volume samples in glass lyophilization vials and demonstrates the potential use of LAD to stabilize products such as vaccines.