Shelf Life Test (Stability Test)

Shelf life test, also known as stability test, is performed in cosmetics and medical products.

Stability tests are generally tests to determine / verify the shelf life of the product. Stability tests are expected not to deteriorate the physicochemical structure of the product and to be suitable for microbiological aspects.

Stability tests can be performed both by holding the product for normal shelf life and by changing the ambient conditions (such as increasing the temperature to accelerate). Stability tests by increasing the temperature are also called accelerated aging tests.

In the accelerated aging test, the test time is shortened by exposing it to temperatures higher than the normal shelf life temperature and results are obtained in a shorter time.

Shelf life of medical products:

Aging tests in medical products are mostly performed as accelerated aging test. The method used for shelf life testing in medical products is ASTM F 1980 standard.

According to this standard, the fast aging time of the product is calculated by taking into account the temperature and real-time shelf life time that the product can withstand according to the structure and packaging characteristics of the product.

An example calculation is given below.

Product real-time shelf life: 3 years (1095 days)

Temperature at which the product will be analyzed: 65 ®C

Stability Test Analysis Time: 56 days

As a result of this calculation performed with the Arrhenius equation, the fast aging time of the product is calculated. At the end of this period, performance tests and physicochemical and microbiological tests are performed.

After the stability test performed in medical products, the starilite test and tightness test are the main tests.

Shelf life of cosmetic products:

It is extremely important that cosmetics are stable in addition to their functional uses. Stability tests enable us to learn the physical, microbial and chemical quality of the product as well as the adequacy of the packaging during storage, transportation, sales and consumption of the end user.

Stability Tests are applied in two ways: Real Time and Accelerated Aging Tests.

Accelerated aging tests are carried out in artificial environments containing temperature and humidity outside normal sales and consumption conditions. After accelerated aging tests, the necessary physical, microbial and chemical analyzes of the product are made to ensure that we have prior knowledge of the stability of the product.

Before starting accelerated aging tests, all the necessary information about the content, packaging and physical structure of the product must be obtained and the information must be notified by the manufacturer in advance. Aging tests of cosmetic products

37®C, 40®C and 45®C at temperatures of 1, 2, 3, 6 months, such as 10%, 55%, 75% in different humidity and light conditions such as waiting is made and the temperature and times vary from product to product . Some products are also applied at low temperatures.

At the end of the holding period, the products are subjected to color, odor, appearance, pH, weight change, viscosity, microbial load and, if necessary, antimicrobial efficacy and packaging tests according to international pharmacopoeia analysis methods. Breaking, cracking and sealing tests of packaging materials are just as important as product tests.

In accelerated aging studies, it should be understood that the analysis parameters determined according to the type of the product can not maintain the stability of the products during the shelf life of the product if the test results show any negativity and the manufacturer should make necessary changes in both the product content and the packaging.

As a result, shelf life tests (Stability Tests / Accelerated Aging Tests) are necessary tests to prevent potential problems that may occur later in the product and to prevent material and moral damage, such as the collecting and recall of the product.