Cosmetics Product Testing: A Must for its Success

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Vinay Kumar Singh.
Chief Research Officer
Parammount Cosmetics India Limited,
Bangalor, Karnataka

Product is successful when it sells in the market and brings profit and revenue for the manufacturer. For a successful product, quality is an important factor for consumer to accept it. In order to ascertain quality of a product, it must be tested on various parameters. Without testing the product, one can not be sure of its quality, safety and efficacy. Before any new product is put in the market, it must be thoroughly tested.

Product testing program involves following:
a) Stability Testing
b) Safety testing
c) Performance/Efficacy testing

Stability testing
Stability testing evaluates a product’s ability to maintain its original aesthetic, physical and chemical characteristics under controlled conditions
designed to accelerate aging. Such testing can provide an early indication of problems that may occur in formulations.

Why stability testing is done?
Stability data is useful as an “early warning system” that alerts a formulator about problems related to formulation, Package etc.
Such advance information can be helpful in many ways: -
• To guide the chemist during product development
• To ensure that the product will continue to be aesthetically acceptable to the consumer.
• To determine that the product will perform as intended and remain safe to use.
• To forewarn the manufacturer about problems which may occur after the consumer has purchased the product.

Thus, stability testing gives us an idea of the future risks and provides us guidelines to lay down a foundation for evaluation of future problems.
When stability testing is done?


Stability testing is done:
• Whenever any new formulation is developed.
• Qualifying new raw material
• A modification in the formula
• A modification in manufacturing process
• Change in immediate packaging.

How Stability testing is done?
Stability testing involves:
•    Testing of formulation in initial stages of product development.
•    Compatibility testing.
Changes that occur in the product over a period of time includes following:
a)    Physical
-    Viscosity
-    Texture
-    Colour
-    Odour
-    Loss of Volatile constituents
-    Uptake of water

b) Chemical
-    pH
-    Degradation of active constituents
-    Interaction between constituents

c)  Microbiological Spoilage
Changes that occur in the container over a period of time includes following:  -    Leakage
-    Corrosion
-    Stress cracking

To obtain the stability data in short time accelerated stability testing is done.
Accelerated stability testing involves exposure of the product to following parameters:
Elevated temperature
Elevated humidity
Cycling tests
Freeze-thaw tests
Exposure to light
Mechanical tests.

(1) Elevated temperature:
Storage at elevated temperature is critical, since the rate of chemical reaction roughly doubles for every ten degree increase in temperature. This test allows us to see certain problems much sooner than they would appear at room temperature. The drawback of this process is that, at high temperature we may be forcing reactions to occur that would not happen at all at lower temperatures.
The most common storage conditions includes 45oC, 54oC, 37oC, 35oC, room temperature, 4oC.
It is recommended to store enough sample to make all the observations required as per your specification.
At each checkpoint product should be checked for following parameters
a) Physical attributes such as colour, odour, viscosity etc.
b) Microbial Challenge test for preservative efficacy
c)  Percentage of actives
d) Functional attributes

(2) Elevated Humidity
Since many products are adversely affected by moisture, storage at elevated humidity normally forms part of stability tests.

(3) Freeze – thaw tests  Subjecting a product to alternate freezing and thawing can be of value in indicating the tendency of liquid products to cloud or crystallize or the physical stability of creams or other liquid of creams or other liquid emulsions.

(4) Cycling tests
Tests under conditions that are periodically changed can impose greater stress on samples than storage under constant conditions. The following are suggested as generally useful cycling conditions.
• 370c / 80% r.h alternating 24 hourly with 200c /ambient humidity.
•  Mean maximum temperature
• Mean maximum humidity alternating 24 hourly with 200c /ambient humidity.

(5) Exposure to sunlight
Where products are likely to be exposed to light in the market or in use, it is necessary to investigate the effect of such exposure. Mostly the effect of sunlight is seen as change in colour of the products.

(6) Mechanical tests
Vibration of samples can be useful in indicating whether demixing is likely to occur in powder or granular products; it can also serve as an indicator of       emulsion stability. Clear definition of test objectives and careful planning of tests can yield the required information most efficiently and in the shortest time.

Compatibility testing goes hand in hand with stability testing. This test highlights the interaction between contents & the immediate container.
These interactions may be of following types
• Sorption of constituents of the contents by the container.
• Leaching of constituents of the container into the contents.
• Adverse effects on the container such as corrosion



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