Cosmetic Stability Testing

COSMETIC STABILITY TESTING

The purpose of stability testing is to ensure the product maintains its intended physical, chemical, and microbiological quality, as well as functionality and aesthetics when stored under the appropriate conditions.  At selected intervals, samples are evaluated for various physical, chemical and performance characteristics to see if and how they have changed.  The product must remain stable and any sign of instability is evaluated to determine if reformulation may be required.

Tests offered include:

• Preliminary Stability Testing - 15 days
• Accelerated Stability Testing - 3 to 6 months
• Real Time Stability Testing - Up to 3 years
• Freeze Thaw and Thermal Cycling Studies - 6 Cycles

We have the capabilities to test organoeliptical properties such as colour, odour & appearance; physiochemical properties such as pH, viscosity and density, microbial count; container compatibility and emulsion creaming.  Finished product samples are evaluated against a standard sample and with reference products subjected to the same test conditions.  The amount of product required will depend on your testing protocol. Testing may also be performed on raw material samples.

PRESERVATIVE  EFFICACY TESTING

Preservative efficacy testing checks your product to see how the preservative system copes when challenged by different types of bacteria over 28 days.  The microbes of known type and concentration are added to your product, then samples are taken on days 0, 7, 14, and 28 and evaluated.  A good result is when no microbes grow, or when tested according to the relevant standards, the preservative reduces the number of colony forming units over time.  The microbes used in this test are Pseudomonas aeruginosa, Staphylococcus aureus, Escherichia coli, Candida albicans, Aspergillus brasiliensis. We also challenge with a Bacillus species to evaluate your preservative's effectiveness against spore forming microorganisms.  Re-challenge testing is also available.

MICROBIOLOGICAL ANALYSIS

We offer one-off single microbiological tests to evaluate raw materials, finished products, packaging, environments, equipment and surfaces for yeast, mould and total bacteria.  This testing is very useful for checking the quality of raw materials and for testing bulk product during manufacturing. To allow time for the growth of fungi, the results of these tests are usually available after 7 days.

TIME KILL TESTS

The effectiveness of antimicrobial agents incorporated into disinfectants, sanitisers and antiseptics is measured by their ability to kill microorganisms within a specified contact time.  To accurately determine this, complete and immediate inactivation (neutralisation) of the antimicrobial agent is required.  Inefficient inactivation could allow the agent to continue killing the microorganisms beyond the exposure time and this would result in an over estimation of antimicrobial activity.

A time kill test measures the changes in a population of aerobic microorganisms over time, after exposure to a test material.  The test material e.g. finished product, is brought into contact with a known population of microorganisms for a specific period.  A neutralisation technique is applied to quench or stop the antimicrobial activity of the test material at different sampling intervals.  The surviving microorganisms are then counted.  The time taken to complete this test because the method for quenching the antimicrobial agent has to be determined and proven to be effective for each material tested, against each microorganism selected for the test. The procedure becomes more complex and time consuming when additional types of microorganisms are included in the test.

WATER QUALITY TESTING

Water is a major component in many formulations.  It is also used in preparatory processes such as rinsing glassware, and other materials.  Using the right kind and quality water is essential for ensuring product quality.  Whether it be purified, demineralised spring water or distilled water, it is highly recommended you have a sample tested to verify its quality.  

Other water samples that we accept for testing include include drinking water, river and bore water, swimming pool, aquarium and spa water.