Cold Chain

The Keys to Effective Temperature-Controlled Monitoring

Cold Chain

14:00, December 6 2017

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Meserve Platt, Supply Chain Logistics Expert, outlines the drivers behind effective temperature monitoring

Maintaining a temperature-controlled supply chain brings a number of challenges to a distribution team. Once you have determined the packaging and method of shipping, the question of monitoring shipments often occurs. The impetus to monitor shipments can come from many different directions. Understanding fully why the shipments need to be monitored can help to select the best solution and reduce the complexity that might be implied by taking a broad application to monitoring. In this piece, I will outline a few drivers for monitoring and some solutions that can be employed.

All of the drivers for temperature monitoring revolve around the acceptable temperature range the product being shipped can tolerate. In some cases the mere exposure to a temperature out of range can degrade the product irreparably. In other situations, the product may be robust, but can only be exposed to minor excursions for short periods of time. These two criteria allow for different solutions to yield acceptable results. Another factor that can drive for monitoring is where there is a desire to monitor more than temperature across time for the shipment. A situation where this could be important is in a clinical trial setting where an opioid is provided as a co-medication, and the sponsor wished to monitor location to avoid diversion. This scenario would require a different solution.

Three Types of Monitors

Let’s first look at types of monitoring and what information can be determined. There are three basic types of monitors that can be employed: tattle-tail devices, recording devices and communicating devices. Tattle-tail indicating devices are single use devices that are passive and designed to visually identify if a temperature was exceeded. These devices can be put into the packaging to monitor the payload, or they are placed on the exterior of the packaging to monitor the conditions that the package is exposed to. These devices are capable of recording only that the excursion did or did not occur.  

They are not able to indicate time, or to indicate the magnitude of the excursion. Both recording devices and communicating devices are active units that use battery power to record, and in the case of communicating devices, communicate. Recording devices come in a variety of forms, from the size of a paperback book to a USB ‘thumb’ drive. These devices often have a display and one or more switches and are capable of recording the temperature with a time stamp.

Some devices have a fixed sampling rate, others can be configured, both usually can monitor for a few days at a minimum. Some require proprietary software, others can generate a graph or PDF from the device. These devices have the advantage of providing continuous monitoring and can provide a detailed picture of the temperature profile for the time monitored. Some can support an external probe, or two channels. These devices are usually configured prior to shipping and are then either returned or ‘read’ upon receipt.

Communicating devices are a newer class of device that are very similar to recording devices, with the added capability of being able to communicate the data via wireless networks, cellular telephone networks or Bluetooth(r) protocols. Communicating devices can often offer additional parameters to record and transmit, such as location. Depending upon the device/communication method, these devices can communicate when they find a network, or when interrogated.

Avoiding Temperature Excursions – Finding the Right Solution

The choice between these devices is affected by two primary factors: how detailed the data needs to be, and the cost – both of the solution and the value of the product being shipped. With products that are colloids, or other products that can be irreparably damaged by freezing (or temperatures above a certain point), Tattle-tail devices can be sufficient. They will provide evidence that the temperature limit has been crossed and the product being shipped is no longer useable. 

When the product can tolerate some excursion of temperature, the recording device is a better choice so that upon receipt, the temperature profile can be reviewed and approved if necessary, prior to use.  Where the value of the product or the compliance to data collection drives the decision, a communicating device is the best choice to ensure that the data can be collected and reviewed prior to use of the shipped product. Yes, Tattle-tail devices are the least expensive, with communicating devices being the most expensive. Yet the cost is commensurate with the type, volume and quality of the data and its accessibility.  

An additional factor when selecting between solutions is the process for retrieving the data to the home office. With Tattle-Tail and recording devices, there needs to be a protocol at the receipt of the product/shipment to transfer the data or result of the monitor back to the home office. While this often occurs in well-used routes with seasoned staff, gaps can be a cause for concern in clinical settings.  Where the product is especially sensitive to temperature excursions, communicating devices may be the best solution. 

Final Considerations

Cost is always a consideration when choosing a solution.  As technology drives features, communication, GPS, alarms, the value proposition improves.  With products demanding more data the choice can be simpler. Additionally the market place has a healthy mix of established companies and new companies. Some sources for devices mentioned here are: Omega Engineering (tattle-tail indicators), ElPro (monitoring devices) and Lab Sensor Services (communicating devices – LE Bluetooth). 

One last factor to consider with active monitoring systems concerns the integrity of the data and data retrieval. For clinical settings and trial conditions, the use of compliant software is a requirement. Most of the suppliers that sell specifically into the health care/diagnostics marketplace offer compliant software to meet these requirements. While technology can overcome some compliance issues, setting up networks and maintaining them can add to the complexity and cost of the process. Monitoring can also help to identify preferred routes and fine tune packaging definitions.

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