Temperature-controlled pharmaceutical shipping systems rely on refrigerants to maintain validated thermal ranges during transport. Two of the most common refrigerant approaches are water-based coolants and phase change materials (PCMs).
Each technology offers different advantages related to:
- temperature stability
- duration performance
- conditioning requirements
- sustainability
- operational flexibility
Understanding how these coolant systems behave helps organizations select the appropriate thermal packaging strategy for specific pharmaceutical and biologic shipping applications.
What Are Water-Based Coolants?
Water-based coolants use water or water-based gel formulations as refrigerants within insulated thermal packaging systems. These coolants help stabilize internal shipment temperatures by absorbing thermal energy and slowing heat transfer during transit.
Because they are relatively simple to condition and widely available, water-based refrigerants remain common across many pharmaceutical distribution networks.
They are often used for:
- parcel shipping
- short-to-medium duration lanes
- refrigerated applications
- standard pharmaceutical distribution workflows
Common Water-Based Coolant Formats
Gel Packs
Flexible refrigerant packs containing gel formulations.
Water Bricks
Rigid refrigerant containers designed for repeatable packout configurations.
Hydrated Panels
Integrated cooling structures used in thermal packaging systems.
Typical Applications
- 2–8°C pharmaceutical shipping
- Controlled room temperature (CRT) shipments
- Last-mile distribution
- Regional parcel delivery
- Clinical trial supply distribution
What Are Phase Change Materials (PCMs)?
Phase change materials (PCMs) are engineered refrigerants designed to maintain specific temperatures during phase transition.
Unlike traditional water-based coolants, PCMs are formulated to transition at targeted thermal points.
During phase transition, PCMs absorb or release energy while maintaining relatively stable temperatures.
This makes them valuable for:
- narrow temperature tolerances
- long-duration shipping
- sensitive biologics
- advanced pharmaceutical applications
How PCMs Work
PCMs store thermal energy during melting and release energy during solidification.
Because the phase transition occurs at engineered temperatures, PCM systems can provide:
- improved thermal stability
- tighter temperature control
- reduced temperature spikes
- extended payload protection
Typical PCM Temperature Profiles
Examples may include:
- 5°C PCM systems
- CRT PCM systems
- Frozen PCM systems
- Deep frozen PCM applications
Actual validated performance depends on:
- packaging configuration
- ambient conditions
- payload characteristics
- shipping duration
Key Differences Between Water-Based Coolants and PCMs
| Feature | Water-Based Coolants | PCM Coolants |
| Temperature Stability | Moderate | High |
| Temperature Precision | Broader ranges | Narrower control |
| Duration Performance | Moderate | Extended |
| Conditioning Complexity | Lower | Higher |
| Cost | Lower | Higher |
| Payload Sensitivity Support | Moderate | High |
| Reusability Potential | Varies | Strong potential |
| Sustainability Potential | Moderate | High in reusable systems |
Benefits of Water-Based Coolants
Water-based refrigerants remain widely used because they are operationally straightforward and adaptable across many shipping environments.
For organizations managing high shipment volumes or standard refrigerated distribution, these systems can provide a cost-effective and familiar solution.
Some of the primary advantages include:
- simpler conditioning workflows
- broad operational acceptance
- flexible packaging configurations
- lower upfront cost compared to some advanced PCM systems
Water-based solutions are often best suited for:
- regional lanes
- lower-risk shipping profiles
- shorter shipment durations
- standard pharmaceutical applications
Benefits of PCM Coolants
PCM systems are often selected when temperature precision and duration stability become more critical.
Because these systems are engineered around targeted phase transition temperatures, they can help reduce the risk of thermal fluctuation during transit.
PCM systems may offer advantages such as:
- improved thermal stability
- reduced excursion risk
- support for sensitive therapies
- extended duration performance
These systems are commonly used for:
- biologics
- cell and gene therapies
- long-duration international shipments
- high-risk or variable shipping lanes
Reusable PCM systems may also support broader sustainability initiatives by reducing packaging waste across repeated shipping cycles.
How Coolant Selection Impacts Thermal Performance
Selecting the appropriate coolant strategy can significantly influence overall shipment performance.
Factors such as:
- shipment duration
- ambient profile
- payload sensitivity
- lane variability
- handling conditions
can all affect how a thermal packaging system performs during transit.
As shipping conditions become more complex, the choice between water-based and PCM refrigerants may become increasingly important.
Considerations for Pharmaceutical Qualification
Thermal packaging systems are typically evaluated using qualification methodologies designed to assess performance under expected shipping conditions.
Qualification activities may include:
- summer and winter testing profiles
- payload configuration analysis
- duration assessments
- operational handling evaluations
The appropriate coolant strategy ultimately depends on:
- validated packaging design
- distribution lane requirements
- stability needs of the pharmaceutical product being transported
Sustainability Considerations
Sustainability continues to play a growing role in pharmaceutical cold chain logistics.
Coolant strategy can affect:
- packaging reuse potential
- shipping efficiency
- waste generation
- reverse logistics workflows
Reusable PCM systems, in particular, may help organizations reduce packaging waste and support longer system lifecycles across repeated shipments.
Choosing the Right Coolant Strategy
There is no single refrigerant approach that fits every pharmaceutical shipment.
The appropriate solution depends on balancing:
- thermal performance
- operational complexity
- shipment duration
- sustainability goals
- payload sensitivity
Organizations evaluating thermal packaging systems often consider:
- shipping lane variability
- product stability requirements
- operational workflows
- compliance expectations
Frequently Asked Questions
What is the difference between PCM and gel packs?
Gel packs typically use water-based refrigerants, while PCMs are engineered to transition at targeted temperatures for tighter thermal control.
Are PCM systems better for biologics?
PCM systems are often used for sensitive biologic shipments because they can provide improved temperature stability.
Do PCM systems last longer?
Some PCM systems can support extended duration performance depending on packaging design and shipping conditions.
Are water-based coolants still used in pharma shipping?
Yes. Water-based refrigerants remain widely used for many pharmaceutical distribution applications.
How are coolant systems qualified?
Thermal shipping systems are generally evaluated using qualification methodologies that assess performance under expected shipping conditions.