Mandatory EU Safety Testing: Compatibility Testing

The purpose of the compatibility test is to evaluate the migration of chemicals between the cosmetic product and its container – primary packaging. Packaging can directly affect finished product stability and safety because of the possible physical and chemical interactions between the product, the package, and the external environment.

The Compatibility test may include:

  • Interaction between the product and the container;
  • Barrier properties of the container;

Several aspects are checked for both the container and the product:

  • Waterproofness of the container;
  • Phthalate concentration in the product;
  • Aging of the container;
  • Stability of the emulsion: there can be 2 phases formed for a product if it is unstable or if there are interactions between the packaging and the product. To check for the stability, the sample is observed both in the original packaging and in a control container usually a glass (inert) container.
  • Restitution test: to check that the whole product is accessible to the user considering its packaging
  • Transportation test

General Considerations

There are no standard protocols for the compatibility testing of the cosmetic products. An appropriate assessment may be made based on the knowledge of the formulation and primary packaging materials and experienced expert judgment.

Test Method

Why: to test the potential migration of small amounts of substances from the primary packaging material to the formulation.

When: before the placing on the market of the cosmetic product and while development or Good Manufacturing Practices or GMP random controls.

How: The environmental conditions and the periodicity of the analysis can be the same as those mentioned for the formulation Stability Studies.

In this test, several alternative container materials may be analyzed to determine which is most suitable for the product.

Types of container material and main evaluations:

1. Cellulose Packaging

  • Examples: cartridges, trays, displays and cardboard packages.
  • What is generally evaluated:
  1. alterations in the paper and formulation structure, checking for possible migration of components that could contaminate the product (e.g.: sachets);
  2. physical-chemical stability of the packaging;
  3. alterations in the formulation – appearance, color, odor, among others;
  4. appearance and functionality of the package;
  5. barrier function (e.g., permeation of oil, water or gases);
  6. metal determination, whenever applicable.

2. Metal Packaging

  • What is generally evaluated:
  1. delamination, when applicable;
  2. corrosion;
  3. alterations in the formulation – appearance, color, odor, among others;
  4. appearance and functionality of the package;
  5. formula reaction;
  6. polish or resin integrity (internal and external);
  7. metal determination, whenever applicable;
  8. functionality.

3. Plastic Packaging

  • Examples: Polypropylene (PP), high density Polyethylene (PEAD), low density Polyethylene (PEBD), Polyethylene Terephthalate (PET), Polystyrene (PS) and Poly vinyl chloride (PVC).
  • What is generally evaluated:
  1. alterations in the formulation – appearance, color, odor, among others;
  2. appearance and functionality of the package;
  3. interaction and migration of components between package and porosity to water vapor;
  4. light transmission;
  5. heat-sealing (whenever applicable);
  6. deformity (collapse or bending).

4. Glass Packaging

  • What is generally evaluated:
  1. alterations in the formulations – appearance, color, odor, among others;
  2. appearance and functionality of the package;
  3. mechanical resistance of the package.

5. Pressurized packaging

  • The evaluations must be in conformity with the characteristics of the previously evaluated materials and also consider the influence of the propellant on the formulation and on the package materials.
  • What is generally evaluated:
  1. performance of the product in accordance with its functionality;
  2. corrosion and electrolysis of the package;
  3. internal and external polish control (porosity), whenever applicable;
  4. homogeneity of coatings and linings – bubble formation, fissures and corrosion;
  5. performance of the valve and it’s components;
  6. presence of electrolytes, odor and formulation precipitation.

Conclusion Report

The conclusion on compatibility report should contain:

  • Identification of the lab conducting the testing
  • Identification of the product
  • Identification of packaging material used in the test
  • A description of the methodology used – the protocol
  • Study conditions (sample storage conditions, test time period and periodicity of the evaluations)
  • The result of the report
  • The signature of the person responsible for the study
  • What to consider based on the conclusion of the report:
  1. If migration is dependent on the storage conditions, the correct conditions should be indicated on the labeling of product.
  2. If the formulation is sensitive to light or air and would degrade in a way that impacts consumer safety or product efficacy, appropriate packaging material should be used.

As an Obelis client, you can take advantage of our network for pre-approved Safety Testing facilities to obtain any tests you may be missing in parallel to the EU Compliance process.

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