IN THE LAB - Testing Chambers | Portable Stability Testing Chambers

By Ron Breuer

Cost-effective chambers offer flexibility and adaptability

The interior of a portable stability testing chamber. When temperature and humidity are distributed evenly throughout, all samples are exposed equally to consistent conditions over extended periods of time.

Stability testing is an essential part of pharmaceutical product development, important to regulatory review, product efficacy, and consumer safety. While necessary, these studies impose a cost burden on drug development and production. How an organization addresses stability testing requirements can lead to either more or less efficiency and expense. This piece will examine the relative cost effectiveness of portable stability test chambers compared to permanently installed testing rooms. Factors influencing this calculation include not only the purchase price per cubic foot for the storage space, but also the costs for maintenance, operations, redundancy, efficiency, flexibility, and what may be referred to as “leave behind.”

Portable chambers offer anywhere from four to 30 ft³ of useable sample space, while built-in rooms typically provide 20 to 400 ft³ of sample storage. A state-of-the-art portable chamber costs between $10,000 and $25,000, depending on its size. A full-sized installed room starts at approximately $40,000 and can cost considerably more. Thus, based on a straight price per ft³ basis, portable chambers are more cost effective.

Considerations

The first consideration is physical space. In a new facility, what are the tradeoffs involved in dedicating floor space to a built-in room? In an existing building, are the space and layout appropriate to accommodate a room? If not, and unless new construction is an option, the decision is made. In some localities it is necessary to add the cost of building permits—and the time it takes to have them approved—to the list of expenses for built-in rooms.

The issue of redundancy comes into play as well. If a room goes down, a comparable amount of space will be needed in which to place samples while the room is brought back online. The chances that all of an organization’s portable stability testing chambers will be offline at the same time are remote at best. Thus, it is typically sufficient to cover approximately 50% of the available space provided by portable chambers for backup. In the event of a local power outage, portable units can be relocated to a portion of the facility or adjoining facilities that still have power. Reduced requirements for backup testing chamber availability are a significant factor when considering the overall budget for acquiring testing capacity. (It should be noted that backup generators are needed at all facilities, independent of whether or not stability testing is done in portable or installed/ built-in rooms.)

The portability of freestanding chambers provides further benefits. The ability to relocate the chambers creates a more flexible facility—they can be moved should it become necessary to change the footprint of storage space. Looking at long-term business trends, an additional benefit can be found when companies change their physical location: the leave-behind factor. This happens more often than plant and business managers may realize. Down-sizing, up-sizing, relocation, mergers, acquisitions, and other factors often cause companies to move portions of their production and or testing facilities. Built-in rooms are left behind. Installed rooms can be disassembled and moved, but with far greater time and expense. This potential future cost should be considered in the overall calculations.

With regard to available space, there are pluses and minuses to both types of stability testing platforms. When really large batches need to be accommodated, it is convenient to have a room large enough that the new samples can be readily added with minimal disturbance or movement of existing samples. Portable chambers provide more flexibility. They can be set for varying parameters, including temperature, relative humidity, and light exposure, which can be important depending on the storage requirements of individual samples and the climate in which the product is to be distributed.

IMAGE COURTESY OF BINDER INC.

On this temperature and humidity chart, the light area indicates the control range of temperature and relative humidity. The hatched area indicates the control range of temperature and relative humidity without condensation. The chamber being measured is a Binder KB 240.

While batches that require different time periods for study are easily accommodated in either chamber or room, there are times when portable units can reduce the amount of record keeping that is necessary if they host an entire batch for the duration of the test. Built-in and installed rooms may more readily accept more kinds of packaging, but larger-capacity portable chambers also accommodate a full variety of containers and packages.

Maintenance is another factor to consider. The equipment that is needed to maintain high and low temperature and humidity conditions in the chambers must run continuously for long periods of time. While most units made today are fairly reliable, they do break down on occasion. It is important to note that the flexibility of the portable chambers when it comes to backup space is important from a maintenance consideration too.

It is also easier to schedule maintenance on portable chambers by doing so when they come offline or even scheduling them to be offline at specific intervals. Taking a room offline is a much more complicated and time-consuming endeavor. In addition, it can sometimes be more difficult to find qualified service personnel for installed rooms, particularly if the installations are heavily customized.

Operational Considerations

Operational factors, while not as significant in the overall picture, still need to be considered. Record keeping for multiple units can be more time consuming. Actually, keeping track of the units, while not normally a problem, can be a cause for concern. Power costs are comparable. Security is easier to accomplish with portable chambers, mainly because their size limits the number of people with access and the number of different sample runs that they contain. If photostability testing is to be conducted on some of the samples, isolating them within a room can prove more troublesome, especially when compared to putting samples in a dedicated unit.

Over the long term, replacement costs must be part of the calculation. This tends to be a gradual process with portable chambers—they don’t usually suffer fatal failures all at the same time. When a room has outlived its usefulness, it must be replaced in its entirety. It is easier to replace testing space a fraction at a time rather than all at once. Replacing units individually also allows organizations to purchase the latest technological advances as the need arises.

In theory, all stability testing chambers are designed to meet all applicable national and international testing specifications and requirements. It is important to buy good quality equipment, whichever type is selected. The equipment should also be backed up by solid and inclusive warranties provided by a company with a proven reputation for customer service. In addition to the long-term savings in replacement and maintenance costs, purchasing well-made products up front will save time, headaches, and money when the costs of downtime and compliance and operational concerns are included.

In the long term, the flexibility and adaptability provided by portable stability chambers lead to clear economic benefits for the consumer. In addition, they provide many functional benefits over the time of their use, and, while not the appropriate choice in all situations, are often easier to use because of their adaptability.

In terms of performance, both types of testing space typically do well. Most manufacturers—some better than others—do at least a reasonable job of putting out units that hold temperature and humidity fairly steadily over long periods of time. While neither type of unit holds an inherent advantage in terms of performance, the flexibility afforded by portable chambers does provide advantages.

Maintaining Temperature and Humidity

Manufacturers of built-in and portable stability testing chambers use different methods to maintain temperature and humidity conditions in their units, and they are not all equal. It is important to look carefully at uniformity throughout the chamber, recovery after door openings, and other measurable and non-quantifiable factors. Shelf design, ease of access, ease of cleaning, resistance to contamination, resistance to ice buildup, data logging and environmental monitoring technologies, and many other factors need to be weighed.

These details can be important in the validation process as well. While validating multiple chambers can add to record keeping, it is simpler to document overall stability of temperature and humidity in a smaller space than it is in a larger space. Validation of chambers dedicated to a specific lot or a small number of lots can often be more readily accomplished.

Stability testing, a critical part of pharmaceutical development, evaluation, and production, is necessary both to meet regulatory review requirements and ensure product safety. Numerous options are available in terms of type and quality of unit, as well as the various technologies used within. In the long term, the flexibility and adaptability provided by portable stability chambers lead to clear economic benefits for the consumer. In addition, they provide many functional benefits over the time of their use, and, while not the appropriate choice in all situations, are often easier to use because of their adaptability.