Keeping Drugs Stable Without Refrigeration

New measurements taken by National Institute of Standards and Technology (NIST) scientists and published in the June edition of Biophysical Journal show that rapidly solidified sugars preserve such proteins best when they suppress tiny, molecular motions lasting a nanosecond or less. NIST scientists Christopher Soles and Marcus Cicerone used instruments at the NIST Center for Neutron Research to help them view nanoscale molecular motions of sugar mixtures that were designed to encase proteins. They found a striking correlation between sugar mixtures that provide unusually good protein stabilization and a suppression of very fast motions in the sugars.

Scientists have known for more than a decade that “glassy” sugars can preserve medicines by encasing the proteins in a protective coating. The NIST measurements show that tiny molecular “wiggling” that facilitates protein degradation occurs at time and length scales smaller than once thought to matter. They found that diluting sugars that become “glassy” at a relatively high temperature with the right amount of glycerol formed a stiffer material, further restricting the protein’s movement. It's as though the sugar glove is now made of cement instead of cloth, says Cicerone.