The instability of vials of lyophilized peptides is one of the major problems in the study of their formulations, and there are many reasons for this. However, there are not many major causes of instability for a vial of lyophilized peptides. A detailed study of the influence of external conditions (such as pH, temperature, light, oxygen concentration, etc.) on the stability of vials of lyophilized peptides helps to design a rational formulation. Although the mechanism by which additives stabilize the vial lyophilization of peptides is not fully understood, the use of additives is still one of the primary means to improve the stability of vial lyophilized peptide formulations. The use of analytical tools such as CD and DSC can help to quickly screen suitable additives.
The cause of the instability of the vial lyophilized peptide
The surface adsorption of proteins is another vexing problem encountered during storage and use. For example, riL-2 adsorbs on the surface of the pipeline during the perfusion process, resulting in loss of activity.
How to determine the solubility of the vial lyophilized peptide from the vial lyophilized peptide sequence?
(1) If vials of lyophilized peptide contain a high proportion of highly hydrophobic amino acids such as Leu, Val, IIe, Met, Phe, and Trp, the vial lyophilized peptide is difficult to dissolve in an aqueous solution or simply not soluble. Any of these amino acids, whether purified or synthesized, may have problems.
(2) Under normal circumstances, the proportion of hydrophobic amino acids is less than 50%. It cannot be continuous with 5 consecutive aa is hydrophobic, the charged amino acids (positive charge K, R, H, N-terminus, negative charge D, E, C The proportion of terminus) is up to 20%, and if the polar N- or C-terminus of the lyophilized peptide in the vial can increase the polar amino acid, it can also improve the solubility.