Most of the biological pharmaceuticals such as proteins, peptides, and oligonucleotides are supplied as aqueous solution or lyophilized solids. To date, insulin is the only biologic available in a crystalline formulation. A crystalline formulation has some advantages over its amorphous counterpart, including (1) high concentration and high purity: In the crystalline form, the protein molecules exist in the most concentrated form and retain an active conformation; (2) possibility of controlled release: The dissolution rate in aqueous solution is low relative to the amorphous material. It may be considered as a carrier-free controlled release form; (3) increased stability: The physical and chemical stabilities of crystalline material may be greater compared to liquid solutions or the amorphous state due to higher purity, more compact molecular arrangement, and restricted molecular motion.
SSCI offers crystallization screening using a variety of crystallization techniques from vapor diffusion to microbatch screening. Initial screening is conducted on a small scale using various vapor diffusion techniques (sitting drop, hanging drop, sandwich drop, and capillary) and batch crystallization techniques (slow evaporation, fast evaporation, and anti-solvent precipitation). The conditions in which crystallization occurs will be further optimized and scaled up. The batch crystallization process can also be applied to large scale purification.
The crystallization techniques described above are also used for single crystal growth of proteins and peptides for three-dimensional structure determination.