Humidity test chambers in laboratories

What is a humidity test chamber ?

Definition

Humidity test chambers , also known as humidity cabinets, create the required conditions for the stability testing of various materials. A humidity test chambers can be used to simulate various temperature and humidity conditions. Lighting simulation can be very important as well for some tests.

There are roughly two types of humidity test chambers : constant and dynamic climate chambers. Humidity test chambers are often employed for long-term stability tests and can be used to maintain temperature and humidity at defined levels. On the other hand, dynamic climate chambers can be used to run specific testing programs in which temperature and humidity are modified automatically at set times.

Humidity test chambers are used in industrial and research settings. Such applications include stress-testing of samples, materials tests, aging tests, long-term stability tests, and use as a specific storage facility.

Steam humidifiers and other important components in the humidity test chambers

Structure

Humidity test chambers are made from many components that work together to create stable temperature, humidity, and lighting conditions. There is an enormous variety of different humidity test chambers available – from compact units for use on laboratory tables to human-sized chambers on casters and large walk-in climate chambers. In order to ensure that tests are as meaningful as possible, precise data collection and recording over the entire duration of tests are essential.

Effective interaction of components and systems in the humidity test chambers

Climate and cooling systems are perfectly fine-tuned to each other and can provide uniform air circulation – even along the side walls and with the interior fully loaded. Homogeneous climatic conditions for all test specimens, regardless of the size and quantity of samples, are vital especially for long-term testing compliant with GLP and GMP standards. A powerful compressor cooling system is normally used to ensure tests are conducted under extreme climatic and on-site conditions, while an independent temperature safety device monitors the data with an optical and acoustic alarm.
The steam humidifier is connected to a drift-free capacitive humidity sensor. This ensures rapid reaction times, precise measurements, short recovery times after opening the doors, and FDA-compliant test results thanks to the microprocessor-controlled humidification and dehumidification system. The steam humidifier is connected to the water supply system which is easy to use (plug-and-play) and offers the option of connecting the system to a domestic water line as well as providing flexible solutions regardless of the water supply and installation site.

More information about the water supply system can be found in the section “Selection”.
With a reliable regulating system, which works in tandem with an HMI (human-machine interface) consisting of a touchscreen display, for example, testing personnel can obtain an overview of all measurement data and can operate the constant climate chamber with ease. The regulating system also ensures documentation is kept regarding measurement data, which is crucial for meeting FDA, GLP, and GMP standards. Furthermore, a digital chart recorder monitors data with reference to defined limits, thus ensuring maximum process reliability.

Stability tests and stress tests in humidity test chambers

Test methods

In order to make use of the results of a stability test, ahumidity test chamber must be guaranteed throughout the test. Even minor external influences may distort results, which is why the quality assurance measures offered by a humidity test chamber are enormously important for various types of stability tests.

The four main types of stability tests

In order to most effectively analyze the behavior of samples, specific types of stability tests have been developed:

Long-term tests: This test method is used to observe the behavior of pharmaceutical products under real-world conditions. The samples are tested at specific temperatures and relative humidities depending on the climatic zones. During this time, the active ingredients in the products are analyzed regularly while they are in the constant climate chamber. Depending on the properties of the specific sample, a long-term test can last up to several years.
On-going stability testing: This method is used to test whether the quality of a specimen can be maintained even beyond its expiry date. GMP standards require continuous analysis of products already on the market in order to guarantee that the quality of pharmaceutical products will not deteriorate after they are introduced.
Accelerated shelf-life testing: These simulate the real-time aging of medicines at shorter timescales. In accelerated aging tests, the samples will tend to be exposed to higher temperatures. For example, using this method a state can be reached within six weeks which, under normal conditions, would only be possible after one year.
Stress tests: The stability test under extreme conditions, e.g. at 60°C and 60% relative humidity, is normally conducted at the beginning of a stability study in order to decide which of these test methods would be most suitable for the active ingredient in question. The stress test is clearly stipulated in the ICH Q1A Guideline. However, only a select few constant climate chambers are capable of carrying out this kind of test method.

Read our Buyer’s Guide to learn about the factors that need to be considered when choosing a constant climate chamber.

Before drugs can be approved, they are required to meet defined quality standards. For this purpose, extensive tests are carried out – some of which are conducted in humidity test chambers . Conducted over a defined period of time, the stability tests are a way of determining expiry dates. The simulation parameters are equivalent to storage at average ambient temperature between 8°C and 25°C. After the test, the drugs are analyzed. The amount of active ingredient in the drug must still be at least 95% intact. If this is not the case, either the expiry date is changed or the drug will not be approved.

Exceptional case: Stress tests for emergency medicine

In the case of emergency medicine, stability tests conducted at average ambient temperatures do not give an accurate indication of a drug’s shelf life because they are also used in extreme climatic zones. Pharmaceutical products must be able to withstand both high and low temperatures. It is therefore important to take account of the International Council for Harmonisation’s recommendations when devising tests. These state that stress tests at +50°C, at freezing and fluctuating temperatures, and with extreme UV exposures must be conducted alongside the regular stability tests. This is the only way to simulate the storage of drugs under outdoor conditions.

Some models of the BINDER constant climate chamber are also suitable for demanding stress tests and precise light-dose control. Click here to go to the product overview.

More and more people are traveling into tropical or arctic regions, and they will sometimes need medical supplies. So knowledge about the behavior of drugs under extreme climatic conditions is becoming increasingly important for medical personnel.

Especially in mountainous regions, rescue operations are conducted at temperatures far below zero. Stress tests in a humidity test chamber are therefore enormously important for emergency medicine. Oxidation, hydrolysis, and decarboxylation are chemical reactions that cause the decay of drugs in extreme light or climatic conditions. Stress tests can be used to determine the extent to which pharmaceutical products are resistant to external effects.

Over a longer period of time, however, the effects of all medicines constantly become weaker. In order to ensure that critical limits are not exceeded under normal conditions (e.g. in hospitals or in private medicine cabinets), long-term tests or (depending on the active ingredient) accelerated shelf-life tests are vital.

Consumers, retailers, and industry standards place high quality requirements on cosmetic products. In this regard, tests carried out to verify the stability of these products and to provide accurate information about the health-related factors of such products are vital.

Stability tests in constant climate chambers are performed under fixed parameters (temperature, relative humidity, and light) and show how an ingredient behaves over a set period of time. The test results can be used to determine the product’s shelf life, and recommendations can be given regarding the storage of the cosmetic product.

Keeping steady analysis parameters and exact planning of the tests is the only way that conclusions can be drawn as to whether a product or ingredient will retain its quality over the entire shelf-life period with its specified storage compounds.

The target markets of cosmetic products are also an important factor when planning stability testing due to the varying climatic conditions. The ICH guidelines Q1A-Q1F are to be used as instructions.

Storage tests for products in the humidity test chamber

In contrast to stability testing, there are no international standards for storage testing. The parameters involved in storage tests are thus defined by the relevant companies themselves in order to ensure more accurate quality assessment.

With cosmetic pencils, for example, a test method has been developed whereby the pencils are stored away for 12 weeks at temperatures between 5°C and 50°C. Then further tests are carried out on the lead of the pencil.

GMP requirements in the cosmetics industry are binding for manufacturers and define all production stages in the manufacturing process of cosmetics.

The general trend in the food industry is moving away from artificial additives and towards natural ones. The challenge faced by food producers is assessing shelf life, which must be tested under real-world conditions. This poses an enormous problem for producers because they constantly have to introduce new products on the market in order to stay competitive. Under these time constraints, it is often impossible to test minimum shelf life under real-time conditions. To overcome this, producers carry out accelerated shelf-life tests, which are an indirect method of measuring the stability of a product which is less time-consuming and involves lower costs compared to long-term tests.

In humidity test chambers, food can be tested at different temperatures, humidity and at different time intervals. Photostability tests also measure the influence of light on certain foods. The stability, color, and shelf life of the products must also be observed under the climatic conditions prevailing in specific countries.

Testing the quality and properties of paper helps manufacturers choose the right material for their packaging. The resilience of paper and other packaging materials can be tested in a constant climate chamber, which in this context is used mainly used to test resistance to aging – in what is known as the T544 test. In this method, the paper is subjected to particularly high temperature and humidity in order to simulate, for example, whether a specific type of paper is suitable for long-term archiving. The paper quality can be categorized into the following properties: brightness, thickness, opacity, folding endurance, and tear resistance.

Touch-sensitive operation is becoming increasingly standard in the automotive industry. In the past, however, touch films have been known to fail during climatic testing, with bubbles forming in the boundary layer. In such cases, the only solution is to use an alternative adhesive, such as atmospheric-pressure plasma. Film bonding is subjected to a stress test that simulates long-term behavior under harsher environmental conditions. The adhesion of the bonds is tested in a 100-hour climatic storage process at 85°C and 85% relative humidity.

Additive manufacturing – also known as 3D printing – is cultivating a new market which is set to grow exponentially over the coming years, while revolutionizing manufacturing processes. Currently, research is under way to find materials for 3D printing that can withstand temperatures over 100°C without any damage. Even today, 3D-printed products are already being tested in climate chambers at temperatures ranging from 75°C to 80°C in order to assess their resistance to deformation when exposed to heat. Furthermore, standards are being developed for stability tests.

Requirements for humidity test chambers: ICH guidelines Q1A(R2), Q1B(R2), and FDA 21 CFR Part 11

Guidelines

Drug safety is a central issue when it comes to protecting patients worldwide. The advance of globalization is a significant challenge to drugs testing. But this problem is not limited to the life sciences sector – it affects numerous other industries as well. Products are required to meet standards all over the world and ensure quality under all conditions. In the industry’s target markets there are different rules and regulations on certification and inspection by regulatory bodies.

In a bid to standardize the various regulations in countries around the world, a number of measures have been taken, one of which is the “good laboratory practice” (GLP) quality system. This system ensures the reliability and the international recognition of data. The values of transparency, traceability, assignment of responsibilities, and safekeeping are particularly important to this approach.

Do you want to see all GLP-related criteria at a glance? Download the BINDER GLP checklist now with no obligation:

Stability testing of new active pharmaceutical ingredients and products in accordance with the ICH Q1A(R2) guideline and photostability testing to Q1B(R2) generates important data for approval applications submitted to the relevant health authorities. In the blog post “humidity test chambers in the pharmaceutical industry”, we outline the criteria that are essential for stability tests in line with the ICH or other international or company-specific requirements.

Humidity test chambers are key when it comes to conducting studies on pharmaceutical products. The procedure followed in such studies is outlined in the guidelines Q1A(R2) and Q1B.

More information can be found on the Options & Accessories page. The performance ranges of the different humidity test chambers vary considerably. For example, as well as meeting all the climatic conditions stipulated by the ICH guidelines, some models also satisfy those of the five climatic zones I to IVb. Such models are extremely versatile and, if required, can be used in combination with each other as universal backups. The next section will explain what you will need to know when choosing the right constant climate chamber.

Each component used in humidity test chambers, from the cooling unit to the sensor, fulfils its purpose and is required to meet certain quality standards. Test phases of materials and drugs often taken many days or weeks. Unexpected outages can quickly turn into a cost trap.

So be sure to choose the quality option: Evaluate the constant climate chamber on the basis of these criteria and you will find the right model for your application.

Constant temperature, humidity, and light intensity can only be achieved through consistent quality.

Humidity test chamber for constant temperature and humidity

What is a humidity test chamber ?

Steam humidifiers and other important components in the humidity test chambers

Effective interaction of components and systems in the humidity test chambers

Watch the video on the BINDER KBF series to learn about the construction and advantages of humidity test chambers :

Stability tests and stress tests in humidity test chambers

The four main types of stability tests