Simulation of air/vacuum desiccation process for high‐quality preservation of proteins

Abstract

AbstractTo achieve high‐quality preservation of biopharmaceuticals in dried state which are originally solved in solutions including protective agents, the dried biopharmaceuticals are expected to be in a vitrified state through a simple and low‐cost drying process at room temperature. In this work, we calculated the drying process (water evaporation) of solution including protective agents, trehalose, to predict the probabilities of crystallization and bubble generation in one dimensional (1D) system. From past research, we know that proteins can be preserved in a good state when the mass ratio of TRE/protein is several hundreds. Thus, the interaction between proteins and water/TRE system are neglected because the same mass ratio of TRE/protein was used in this work. Water transportation in both preservative solution and surrounding ambient gas during desiccation process was calculated using the super‐saturated water diffusion coefficient which was previously measured by authors group. The water molarity distribution as well as the amount of retained water were obtained both for the vacuum desiccation processes, and the results were compared with the experimental results. The probabilities of dihydrate and bubble nucleation in trehalose solution during the desiccation were predicted based on the classical nucleation theory. The calculated results of the water molarity distribution and the probabilities of crystallization and bubble nucleation agree well with the experimental results, which suggests that the proposed evaporation model may help to find an ideal desiccation process of preservative solution.Practical ApplicationsDrying is a conventional technology for stabilizing the pharmaceutics and foods. The preservative solution including biomaterials is expected to be vitrified uniformly to preserve their function. Freeze‐drying is widely used to remove the water without deteriorating the materials. However, the freeze‐drying has several drawbacks, including the long drying process and the high cost. Thus, considering the disadvantage of the freeze‐drying, a simple high quality vacuum desiccation at room temperature is an ideal technique. Vacuum desiccation utilizes the application of low pressure to enhance the rate of dehydration, and it does not require the solution to be spread in an open environment. Thus, concerning these advantages, vacuum desiccation at room temperature may lead to improve the quality of desiccated biomaterials.