Vial, spray or strip: what the format changes
The same compound in three packages is three different stability, handling and arithmetic problems.
Format is not packaging. A lyophilized vial, an aqueous solution and a cast film put the same molecule into three different chemical situations, and the chemical differences are larger than the price difference.
Lyophilized vial
Dry, sealed and cold, a peptide is about as stable as it gets, which is why the certificate's valid-until date for the dry solid is measured in years. Converting the label mass into a peptide mass needs the lot's net peptide content.
Aqueous solution
A formulated solution holds the peptide with a buffer, a preservative and other excipients chosen for it, and the shelf life of the sealed bottle is set by stability data (buffer, pH and preservative). Its concentration is set at manufacture and stated on the certificate.
Cast film
A film is a cast polymer matrix with the peptide dispersed through it. Its peptide content is set at manufacture and stated on the certificate, and its stability depends on the polymer and its residual moisture.
| Vial | Solution | Film | |
|---|---|---|---|
| Physical form | Dry solid | Formulated solution | Cast polymer film |
| Stable as supplied | Years, dry and cold | Months, sealed | Months, sealed and dry |
| What the certificate must cover | Purity, identity, net peptide content | Plus excipients, pH, preservative content | Plus polymer, residual moisture |
Common questions
What is the difference between a lyophilized vial, a solution and a film?
They put the same molecule into three different chemical situations. A lyophilized vial is a dry solid, an aqueous solution holds the peptide with a buffer, a preservative and other excipients, and a film is a cast polymer matrix with the peptide dispersed through it.
Which peptide format is the most stable as supplied?
The lyophilized vial is. Dry, sealed and cold, a peptide is about as stable as it gets, and the certificate's valid-until date for the dry solid is measured in years. A sealed solution and a sealed, dry film are each stable as supplied for months.
What should a certificate cover for a peptide solution or film?
It should cover more than a vial certificate does. A vial certificate covers purity, identity and net peptide content. A solution adds excipients, pH and preservative content, and a film adds the polymer and residual moisture. In both, the concentration or peptide content is set at manufacture and stated on the certificate.
Is every peptide available as a solution or a film?
No. Availability is not uniform across formats. Most of the catalog is lyophilized vials, and the solutions and films exist for a handful of compounds. That is a manufacturing fact, not an editorial choice.
For laboratory research use only. Not a drug, not a supplement, and nothing here is a claim about what any of this material does in a person or an animal.
