Stabilization study of inactivated foot and mouth disease virus vaccine by size-exclusion HPLC and differential scanning calorimetry

The inactivated foot and mouth disease virus (FMDV), which has a sedimentation coefficient of 146S, is crucial to the efficacy of vaccine preparations, but extremely unstable in vitro. It is prone to dissociate into smaller particles referred to as 12S with a concomitant decrease in immunogenicity; therefore, it is of great importance to find the best condition for stabilizing the FMDV. In the present work, the effects of solution pH and temperature on the dissociation of 146S was investigated and potential stabilizers were screened, with aid of high-performance size-exclusion chromatography (HPSEC) for rapid and quantitative determination of 146S, together with differential scanning calorimetry (DSC) technology for thermal stability analysis. The most stable pH was found between 7.5 and 8.0. Among excipients tested, sucrose and glycerol provided the best protection, such that the half-life of 146S in solution at 45 °C could be prolonged from less than 30 min to more than 3 days by adding 20% sucrose. The stabilization mechanism was confirmed using DSC analysis, which showed that the transition temperature related to 146S dissociation was increased by 5.4 °C in the presence of 20% sucrose. The physical stabilization effects afforded by these stabilizers would allow for the retaining of effective 146S antigens during transportation and storage under relative harsh condition.