Developing a Light-Assisted Drying Technique to Thermally Stabilize Poliovirus Vaccine*

The majority of vaccines are delivered as liquids requiring storage at or below 4°C. In resource-limited areas, this need for refrigeration is a significant cause of undervaccination. Light-assisted drying (LAD) is a novel method to stabilize vaccines at room temperature by drying them in a sugar matrix. In this process, a liquid vaccine and trehalose buffer are illuminated with an infrared laser, rapidly drying the sample and forming a stable storage matrix. This study aimed to determine LAD criteria for processing the poliovirus vaccine (IPOL). Vaccine samples of 0.5 mL were illuminated with a 1064 nm laser in glass tubes for 170 minutes. Polarized light imaging was used to detect sugar crystals, which indicate uneven drying and potential sample damage. Rapid drying is crucial to prevent sugar crystallization, as it can lead to sample degradation. High vaccine concentrations in solution may also cause aggregation and uneven drying. In this study, IPOL samples produced more crystals than previously observed. This was attributed to excess salts in the commercial vaccine buffer. Replacing the buffer significantly improved the drying process, reducing crystallization and improving sample stability.