Unleashing the Potential of Virtual Temperature Buffering
Episode 1: Analyzing the Thermal Characteristics of Diverse Storage Devices
Over the next several weeks, the staff at PharmaWatch™ will delve into the world of temperature buffering. The CDC publication Vaccine Storage and Handling Tool Kit mandates that temperature buffering be outlined when monitoring stored goods. In this series, we will explore the various benefits of thermal buffering, inviting you to be part of this learning community. In this chapter, the characteristics of the stored goods will be explored.
Thermal buffering helps effectively simulate the thermal properties of the items stored in the refrigerator, providing a more realistic measurement of the temperature conditions experienced by the stored products. This knowledge empowers you to make informed decisions in your daily tasks.
When specifying the thermal buffer for stored goods, the number, size, and physical nature of the specimens should be considered. Monitoring the specimens’ storage environment to ensure quality and long-term efficacy is the best practice for improved patient outcomes. Many factors should be considered when choosing a temperature monitoring solution. The first is the temperature range to be monitored. The temperatures being monitored necessitate the use of specific buffer materials appropriate for each range.
- Cryogenic temperatures -196°C
- Ultra-Cold -80°C
- Freezer -45 to -20°C
- Refrigerator 2 to 8°C
- Incubators at 35°C
Each temperature range necessitates specific sensing technology to ensure the accuracy of measurements, a crucial aspect for effective temperature monitoring.
For instance, a cornea chamber, a specialized device used in ophthalmology and research to study and maintain corneal tissues, is a practical example of the need for specific temperature buffering.
Similarly, one should not compare the response of a thermal buffer that may be 5, 10, or 20 times greater in volume than the one stored in the unit.
Granted, thermal buffers are unavailable in every storage unit volume; however, an average volume should be chosen for general measurement purposes when using a physical buffer. Alternatively, one could choose a buffer volume representing the smallest of stored materials.
Buffer Size Response Comparison (Warming)
Accurate buffer sizing is critical when simulating the measured temperature with the stored good. The above graph represents the temperature experience of glycol buffers of differing volumes exposed to the same condition. The refrigerator was warmed (fault condition – door ajar). Starting at 5.0 degrees Celsius, the time required for each probe to reach 8.0 degrees Celsius was measured. The difference between the air temperature (un-buffered) and 20ml buffer reaching the 8.0-degree level is 18 minutes. For a 100ml buffer, this difference is over 60 minutes. A similar observation is made when examining the same parameter for cooling conditions.
Understanding the geometry of stored materials is also crucial. Without this understanding, the extent and effect of a temperature excursion cannot be accurately measured, leaving us to speculate.
This knowledge empowers us to make informed decisions and ensures the safety and efficacy of our storage practices. Unleashing the ingenuity of vvirtual thermal buffering using a PharmaWatch™ sensor removes unknown temperature variables and implements the best practices to help ensure material efficacy. In our next installment, we will highlight how virtual temperature buffering brings about a new era of control.
Written by Michael Rusnack
