- Document
- CC-03
- Section
- Cold chain & receiving
- Revised
- Sources checked
- Bands
- −80 °C−20 °C2–8 °C
Storage Equipment and Temperature Monitoring
Choosing and running freezers and refrigerators for peptide storage: manual vs frost-free defrost, probe placement, alarms, mapping and what to do when a unit fails.
Bench card
- Use manual-defrost or ultra-low freezers for frozen stock; avoid frost-free units.
- Monitor continuously with a calibrated probe placed among the samples, not by the door.
- Set alarms with a response plan and a tested contact list.
- Avoid household combination fridge-freezers, which swing widely in temperature.
- Plan for failure: back-up space, dry ice supply and a transfer procedure.
Storage equipment is where peptides spend almost all of their life. A good unit, properly monitored, protects material for years; a poor one, or a good one nobody is watching, can undo careful handling in a single weekend.
Choosing a unit
| Unit | Band | Notes |
|---|---|---|
| Ultra-low freezer | −80 °C | Best for solutions and archives; needs space, power and maintenance |
| Manual-defrost laboratory freezer | −20 °C | The standard for lyophilized stock; defrost on a schedule |
| Frost-free freezer | −20 °C nominal | Warms during defrost cycles; avoid for frozen solutions |
| Purpose-built laboratory refrigerator | 2–8 °C | Even temperature, fan circulation, alarm ports |
| Household combination unit | Variable | Large swings and cold spots; avoid for valuable material |
The CDC Vaccine Storage and Handling Toolkit, written for vaccines but widely applicable, recommends purpose-built or pharmaceutical-grade units and advises against the freezer compartment of household combination units because of their temperature variability.
Monitoring
- Continuous logging: a digital data logger with a calibrated probe records minimum, maximum and current temperature.
- Buffered probes: a probe in glycol or glass beads reads closer to product temperature than one measuring air, and gives fewer false alarms when the door opens.
- Placement: put the probe in the middle of the space where samples sit, not by the door, walls or evaporator.
- Calibration: use probes with a current calibration certificate and recheck on a schedule.
Monitoring is what connects your storage to any stability claim. Shelf lives and retest dates, such as those set under ICH Q1A(R2), assume material was held at defined conditions; an unmonitored unit cannot show that it was.
Alarms and response
An alarm is only useful if someone responds. Decide the alarm thresholds, who is called and in what order, and what they do. Post the plan on the unit. Test the alarm and the call list periodically; the monthly audit checklist includes this.
CL-02
Setting up a storage location
For a new freezer shelf, rack or box that will hold peptide stock.
When a unit fails
- Keep the door closed while you organize. A full, closed freezer warms slowly.
- Move contents to a back-up unit, or use dry ice in insulated boxes as a short-term measure.
- Record the time the failure was found, the highest temperature reached, and how long it lasted.
- Assess affected material by form and exposure. A frozen solution that partly thawed has been through a freeze/thaw cycle, with the stresses Bhatnagar and colleagues describe. See Cold Chain Considerations on judging excursions.
- Repair, verify and monitor the unit before moving material back.
References
- Centers for Disease Control and Prevention. Vaccine Storage and Handling Toolkit (temperature monitoring with digital data loggers).
- USP General Chapter <1079> Good Storage and Distribution Practices for Drug Products. United States Pharmacopeia.
- World Health Organization. Model guidance for the storage and transport of time- and temperature-sensitive pharmaceutical products. WHO Technical Report Series No. 961, Annex 9; 2011.
- USP General Chapter <659> Packaging and Storage Requirements (definitions of controlled room temperature, refrigerator and freezer). United States Pharmacopeia.
- ICH Q1A(R2). Stability Testing of New Drug Substances and Products. International Council for Harmonisation, 2003. ICH
- Bhatnagar BS, Bogner RH, Pikal MJ. Protein stability during freezing: separation of stresses and mechanisms of protein stabilization. Pharm Dev Technol. 2007;12(5):505–523. DOI