Lyophilization¶
Definition¶
Lyophilization (freeze-drying) is a dehydration process that freezes the peptide solution and then removes the water by sublimation under vacuum, leaving a stable, dry powder.
Overview¶
Most research peptides are supplied as lyophilized (freeze-dried) powders. Lyophilization is the preferred method for producing stable peptide products because it removes water that would otherwise promote degradation reactions (hydrolysis, aggregation, oxidation).
Technical Explanation¶
The Lyophilization Process:
| Stage | Description | Purpose |
|---|---|---|
| Freezing | Solution cooled below eutectic point | Immobilizes components |
| Primary Drying | Vacuum applied, ice sublimes | Removes ~95% of water |
| Secondary Drying | Temperature raised, bound water desorbed | Reduces residual moisture to <2% |
Advantages: - Dramatically improves long-term stability (years at -20°C) - Preserves peptide structure and activity - Rapid rehydration upon reconstitution (easy to use) - Reduced shipping weight and no cold-chain requirement
Cake Appearance: A well-formed lyophilized cake is typically an intact, white to off-white powder/pellet. Cracking, shrinkage, or collapse may indicate suboptimal lyophilization parameters.
Importance in Peptide Documentation¶
The lyophilized form is the standard presentation for research peptides. Storage recommendations, shelf-life data, and reconstitution volumes are all based on the lyophilized product. The appearance of the lyophilized cake is noted on the COA as a quality indicator.
Related Terms¶
Frequently Asked Questions¶
Q: How long does lyophilized peptide last? A: When stored properly at -20°C, lyophilized peptides typically remain stable for 12–24 months or longer, depending on the specific peptide.
Q: Is the lyophilized cake weight the same as the peptide content? A: No. The cake includes the peptide, counter-ion, and residual water. The actual peptide content (assay) is lower than the total cake weight.