Project on how freeze-dried carbohydrates can stabilize proteins

Could you please explain what the project is about and what you hope to uncover/understand?

"Drying the formulations to a solid state through lyophilization is a useful way to extend the stability and shelf-life of pharmaceutics for a variety of long-term treatments and applications. The goal of this project is to examine how lyophilized materials, such as sugar (sucrose), can stabilize the structure of proteins (lysozyme). Our strategy is to take advantage of cutting-edge solid-state NMR (ssNMR) technology, which can provide unique details about the dynamics and interactions at the molecular level (such as mobility and/or rigidity) of sugar and protein molecule segments under different hydration and temperature conditions. The present outcome can complement the findings of previous studies that used other methods, e.g., DSC and SAXS."

 Which partners are involved?

"The work is performed in collaboration between MAU (Vitaly Kocherbitov and Vasantha Gowda) and CR Competence (Tobias Halthur and Enamul Mojumdar). We have also involved Daniel Topgaard at Lund University for instrument access and expertise."

 Can you tell us a little bit about the results so far and what they mean?

"Our initial NMR data reveal broad line characteristics for both pure sucrose and lysozyme as well as formulations (80/20 and 60/40 of sucrose/lysozyme), indicating solid amorphous materials without any evidence of molecular segmental mobility at room temperature (25 °C), below freezing (around –8 °C), and above freezing (40 °C). Although the freeze-dried samples showed evidence of residual water, this did not affect the mobilization of sugar or protein. An additional increase in temperature to 70 °C did not change the material´s amorphous behavior or line shape, except for pure sucrose. Pure sucrose exhibited sharp NMR signals and mobility in the sugar molecular segments at 70 °C and even after cooling back down to 25 °C, indicating the sugar's crystallization behavior."

 What will be the next step? 

"Our subsequent objective is to investigate the effects of water and humidity on freeze-dried materials, given its significant influence on the stability and storage of solid pharmaceutics. We began our examination at a low humidity of 33% RH (exposed post freeze-drying) and will thereafter continue to investigate at greater humidities of 53% and above. By using ssNMR in conjunction with controlled humidities and temperature variations, we seek to elucidate the synergistic effects of sugar and protein in great detail."