Peptide vials are an essential tool in the peptide synthesis process. They are a safe and convenient way to store peptides in solution until they are ready for cleavage or other post-synthesis manipulations. A quality peptide vial is important to prevent contamination with moisture, which can severely degrade the peptide’s long term stability. Peptides in solution must be stored under dry inert gas conditions to ensure their long-term storage stability.
How much peptide is in a peptide vial?
The peptide in a vial will vary depending on the sequence and on the presence of certain amino acid residues. For example, peptides containing Cys, Met or Trp are particularly susceptible to oxidation and require anaerobic storage conditions to maintain stability. Other amino acids such as Arg, Asp, His or Lys can absorb moisture from the air and form a water-soluble solution (called deliquescence). Therefore, it is best to store peptides in a vial filled with sterile buffers and capped tightly.
During the process of peptide manufacture, it is important to ensure that the contents of each vial are accurately and completely weighed and the exact weight indicated on the peptide label and instructions. This is especially critical when it comes to lyophilized peptides, where the content of each vial must be clearly defined. The bulk peptide material is precisely weighed and then solubilized to obtain an HPLC determination that defines the content of each lyophilized vialed peptide. This content is then compared with the content of the corresponding USP reference standard to assign a value for each lyophilized peptide.