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Cold chain in transit, and the first hour after a box arrives
Sep
A lyophilized peptide keeps best sealed, dry, dark and cold. Water and heat drive most of the chemistry that degrades a peptide, and freeze drying has already removed most of the water.
That changes what matters on arrival. A sealed dry vial handles a short warm spell far better than it handles water, and the easiest way to let water in is to open a vial while it is still cold.
Lyophilized peptide storage comes down to controlling water and temperature from the day a batch is tested to the day a vial is used in research. A certificate reports what a purity number measures on its test date. Storage and handling decide how closely the vial in your freezer still matches that result.
This article covers sealed vials only, from transit to the freezer. It does not cover anything that happens after a vial is opened.
Why lyophilized peptide storage is about water and heat
A review of solid state stability in proteins and peptides lists the major reactions as deamidation, peptide bond cleavage, oxidation, the Maillard reaction, beta elimination and dimerization or aggregation. It names temperature and moisture content among the factors that control them.
| Route | What changes | What speeds it |
|---|---|---|
| Hydrolysis | Water breaks a peptide bond and splits the chain | Water and heat |
| Deamidation | An asparagine side chain loses its amide group through a ring shaped intermediate | Water, heat and the neighboring residue |
| Oxidation | Sulfur containing and aromatic side chains react with oxygen species | Oxidants, metal ions, light and heat |
| Aggregation | Molecules join into dimers and larger species | Heat and moisture |
With water present, these reactions can be fast. In a model hexapeptide held at 37 degrees Celsius and pH 7.4, the asparagine residue deamidated with a half life of only 1.4 days. The same work found that replacing the glycine next to that asparagine with a bulkier residue slowed degradation 33 to 50 fold.
Freeze drying removes most of the water these reactions need, and cold slows whatever chemistry remains. Neither stops it. Even in the solid state, chemical and physical degradation can occur on the time scale of drying, distribution and use. Dry and cold buy time. They do not make a peptide inert.
Moisture is the main risk to a dry cake
A lyophilized cake is a dry solid that readily absorbs water vapor from the air around it. In a study of lyophilized antibody formulations, samples equilibrated at different relative humidities reached residual moistures from under 1 percent up to 17 percent.
Formulation scientists describe lyophilized products as often sensitive to moisture, and note that high residual moisture can cause chemical degradation through hydrolysis. Glass vials are chosen partly because glass is a good moisture and oxygen barrier, and stoppers are chosen for low moisture content and low vapor transmission. The sealed vial is the moisture barrier. Keep the closure intact and undisturbed for as long as the vial is in storage.
One handling step can undo that barrier: opening a vial while it is still cold. Dew point is the temperature to which air must be cooled to reach saturation. A vial straight from a freezer at minus 20 degrees Celsius sits well below the dew point of ordinary indoor air, so the air touching the glass cools past saturation and water condenses on it. On the outside of a sealed vial, that film does no harm. If the stopper is lifted while the glass and cake are still cold, the same process can put water straight onto the cake.
A sealed vial should come to room temperature before the cap or stopper is disturbed. Leave it closed on the bench until the glass no longer feels cold and any condensation on the outside has dried.
Light and repeated warming
Light is the third variable. Oxidation of methionine, cysteine, histidine, tryptophan and tyrosine residues can be induced by light and is also influenced by temperature. A vial in storage belongs in its carton or a closed box, not on an open shelf.
Repeated warming is the quieter problem. Each trip out of the freezer adds warm time and another chance for condensation, and those exposures add up.
- Keep it dark. Store vials in their carton or a closed box inside the freezer.
- Limit trips out. Retrieve only the vial you need and return the rest to storage without delay.
- Keep it sealed. The closure is the moisture barrier, so leave it intact until the vial has reached room temperature.
What insulated packaging does in transit
Insulation slows the exchange of heat between the inside of a box and the air outside. It does not make cold. A WHO technical supplement on shipping containers defines passive systems as insulated enclosures that hold temperature using a finite amount of preconditioned coolant. It also says a container’s performance must be qualified against the route, the expected outside temperatures and the duration of transport. The same document measures transport time from the moment a package is sealed until it is opened at the recipient’s temperature controlled store. The exposure does not end when the box reaches the door. It ends when the contents reach storage.
For a sealed dry vial, a short warm period matters less than a long one, but it is not nothing. FDA stability guidance shows how drug developers approach it. For drug substances intended for storage in a freezer, the long term condition is minus 20 degrees Celsius, plus or minus 5 degrees, and testing at an elevated temperature is used to address short term excursions during shipping or handling. The same guidance names temperature, humidity and light as the environmental factors that stability testing examines. The effect of an excursion is something to measure, not assume.
Degradation in a dry solid is slow but cumulative. A few warm hours add a little; a day in a hot vehicle adds far more. Unpacking promptly is the part the lab controls.
Imperial Biolab holds stock at minus 20 degrees Celsius until picking, packs orders insulated and ships within the United States only. Shipping terms are on the shipping and returns page.
The first hour after a box arrives
Check the seal first. A cracked vial, a loose or missing cap, or a stopper sitting visibly out of place means the moisture barrier may be compromised.
Then match the batch. Imperial Biolab prints the batch number on every vial, and a QR code on the label opens the certificate for that exact batch. Confirm that the number on the vial matches the number on the certificate, then read the certificate itself; reading a certificate of analysis line by line walks through each field. Every certificate sits in the certificate library and stays online after a batch sells out.
Keep a batch record for each vial: batch number, date received, the condition of the box and vials on arrival, and the freezer location. If a seal or a batch number does not check out, keep the vial sealed and use the contact page before it goes into any work.
- Unpack the box as soon as it arrives
- Check each vial for cracks, a loose cap or a displaced stopper
- Match the batch number on the vial to its certificate
- Keep every vial sealed, with no cap or stopper disturbed
- Move the vials to freezer storage at minus 20 degrees Celsius
- Store them in a carton or closed box, away from light
- Record batch number, date received, arrival condition and freezer location
- Water and heat drive hydrolysis, deamidation, oxidation and aggregation
- A lyophilized cake absorbs water vapor, so the sealed vial is the moisture barrier
- A cold vial should reach room temperature before the cap or stopper is disturbed
- Insulated packaging slows warming but does not stop it
- On arrival, check the seal, match the batch to its certificate and move the vial to the freezer
Frequently asked questions
Sealed, dry, dark and cold. Keep each vial closed in its carton or a closed box and move it to freezer storage at minus 20 degrees Celsius soon after the box is opened. Cold slows the chemical reactions that remain possible in a dry solid, and the intact closure keeps out the water vapor that would speed them up.
Not necessarily. A sealed dry vial tolerates a short warm period far better than a peptide exposed to water, because the main degradation routes depend heavily on water and heat together. It is not without risk, though. Degradation in the solid state is slow but cumulative. Note the arrival condition in the batch record, keep the vial sealed, move it to the freezer and raise any concern with the supplier.
A cold vial sits below the dew point of room air, so water condenses on the glass. If the stopper is lifted while the vial is still cold, that moisture can reach the cake. A lyophilized cake absorbs water readily, and water drives hydrolysis, deamidation and aggregation. Leaving the vial sealed on the bench until it reaches room temperature keeps condensation on the outside of the glass, where it does no harm.
No. Insulation slows the exchange of heat between the contents and the outside air, and any coolant inside is finite. How long a package holds its temperature depends on the packing, the outside conditions and the time in transit. That is why the time between delivery and freezer storage matters. The exposure continues until the vial is unpacked and stored.
The batch number. The number printed on the vial should be the same one shown on the certificate of analysis, which also names the testing laboratory, the test date, the method and the results. If the numbers differ, set the vial aside, keep it sealed and contact the supplier before it goes into any work.
- Lai MC, Topp EM, 1999. Solid-state chemical stability of proteins and peptides. Journal of Pharmaceutical Sciences, 88(5), 489 to 500. DOI
- Geiger T, Clarke S, 1987. Deamidation, isomerization, and racemization at asparaginyl and aspartyl residues in peptides. Succinimide-linked reactions that contribute to protein degradation. Journal of Biological Chemistry, 262(2), 785 to 794. DOI
- Chang LL, Pikal MJ, 2009. Mechanisms of protein stabilization in the solid state. Journal of Pharmaceutical Sciences, 98(9), 2886 to 2908. DOI
- Chang LL, Shepherd D, et al., 2005. Effect of sorbitol and residual moisture on the stability of lyophilized antibodies: implications for the mechanism of protein stabilization in the solid state. Journal of Pharmaceutical Sciences, 94(7), 1445 to 1455. DOI
- Cheng Y, Duong HTT, et al., 2025. Practical advice in the development of a lyophilized protein drug product. Antibody Therapeutics, 8(1), 13 to 25. DOI
- Dew point. National Weather Service Glossary. NOAA National Weather Service. View source
- Li S, Schöneich C, Borchardt RT, 1995. Chemical instability of protein pharmaceuticals: mechanisms of oxidation and strategies for stabilization. Biotechnology and Bioengineering, 48(5), 490 to 500. DOI
- Qualification of shipping containers. Technical supplement to WHO Technical Report Series, No. 961, 2011, Annex 9. WHO, May 2015. View source
- Guidance for Industry: Q1A(R2) Stability Testing of New Drug Substances and Products. FDA, November 2003. View source
This article is general educational information about laboratory analysis and material handling. It is not medical, legal or regulatory advice, and nothing in it describes or recommends the use of any compound in people or animals. Materials supplied by Imperial Biolab are for research use only: not for human or veterinary use, not for diagnostic use, and not for use as a food, drug, dietary supplement or cosmetic. Sale is restricted to adults aged 21 or over. See the research use disclaimer for details.
