Packaging Contact with Cosmetic Formulations: Requirements and Standards

Throughout its shelf life, packaging remains in direct contact with the formulation inside. As a result, it can influence product scent, color, texture, stability, and safety. Ensuring correct dimensions or dispenser fit is not enough—you must also confirm that the packaging material does not adversely affect the cosmetic, and that the formula does not degrade the container, closure, or internal seals.

Compatibility evaluations must be conducted using the final formulation inside the target packaging. Reliable assessments cannot be made solely based on plastic type names or general supplier declarations.

What Does Contact with the Formulation Entail?

Contact between a cosmetic and its container can lead to migration, where components from the packaging leach into the product. These may include dyes, processing aids, production residues, or degradation byproducts.

The reverse phenomenon, known as sorption, is also possible. It means that cosmetic ingredients are absorbed by the packaging material or deposited on its surface. This can impact fragrances, essential oils, preservatives, and active ingredients.

Formulations can also react chemically or physically with packaging. This can lead to swelling seals, plastic clouding, metal corrosion, weakened container walls, or loss of leak-tightness.

Packaging Compatibility Criteria

Compatible packaging preserves its integrity throughout the product's declared shelf life without causing unacceptable changes to the cosmetic. Evaluation must cover not just the primary bottle or jar, but also the pump, dip tube, cap, membrane, gasket, and protective coatings.

Primary compatibility criteria include:

• No significant changes in scent, color, pH, or viscosity
• Maintained leak-tightness and dispenser functionality
• No cracking, deformation, or material swelling
• No substance migration that compromises product safety

Material selection should account for the formula composition, application method, shelf life, and anticipated transport conditions.

Legal Requirements for Cosmetic Packaging

Regulation (EC) No 1223/2009 mandates that cosmetics placed on the EU market must be safe for human health. Packaging materials must be explicitly evaluated within the Cosmetic Product Safety Report (CPSR).

While regulations do not provide a single, exhaustive list of approved materials for cosmetics, the entity responsible for the product must prove that the packaging does not negatively impact safety, quality, or stability.

Manufacturing must adhere to Good Manufacturing Practice (GMP) guidelines. Under ISO 22716, this includes controlling, receiving, storing, and identifying packaging materials. While food-contact data can support safety evaluations, it does not replace testing with the specific cosmetic formula.

Standards for Compatibility Assessment

No single standard defines a universal testing program for every cosmetic and package type. Testing scope should be derived from a risk assessment considering formula composition, material properties, and product usage.

While ISO 22716 outlines GMP principles and ISO 22715 covers general cosmetic packaging and labeling, neither replaces real-time stability testing of the finished product in its final container. Depending on identified risks, specialized testing for migration, seal integrity, water vapor permeability, or oxygen transmission may also be necessary.

Risks of Mass–Packaging Interactions

Packaging materials can leach monomers, stabilizers, pigments, adhesives, coating components, and degradation products into the formula. Conversely, formula ingredients can degrade packaging. Risks are heightened by alcohols, essential oils, fragrances, solvents, acids, and high oil phase contents.

Unfavorable interactions can cause:

• Shifts in scent, pH, viscosity, or color
• Loss of active ingredient efficacy
• Packaging deformation or pump blockage
• Moisture, oxygen, or volatile ingredient migration
• Microbial contamination following a loss of seal integrity

Permeation may also occur, meaning that gases, water vapor, or volatile ingredients pass through the plastic walls, which can lead to water loss, oxidation, or changes in product properties, such as its scent.

NIAS: Identification and Risk Assessment

Non-Intentionally Added Substances (NIAS) require dedicated evaluation. These are unplanned substances that may appear in the material as production residues or as a result of plastic aging.

NIAS can include polymer breakdown products, reaction residues, raw material impurities, or compounds created through interactions between additives. These substances can subsequently migrate into the cosmetic mass.

Evaluating NIAS is more complex than analyzing intentionally added ingredients because their exact chemical profile may not be fully known initially. Depending on the risk level, advanced chemical analysis and toxicological evaluations may be required.

Matching Packaging Material to the Formula

No single packaging material is suitable for every cosmetic. Glass is chemically inert, making it ideal for sensitive or high-active formulations, though its weight and fragility are drawbacks. Plastics like PET, PE, and PP vary in chemical resistance, rigidity, flexibility, and gas permeability, making them suited for different applications while remaining significantly lighter than glass.

For formulations with high alcohol or fragrance concentrations, evaluating chemical stress cracking and wall degradation is vital. Oil-based formulas can cause elastomeric parts (like seals or soft pump components) to swell or lose tightness. Formulations with a low pH require verification of metal parts to prevent surface corrosion.

Compatibility Testing Plans and Risk Assessment Methods

A robust testing program evaluates the cosmetic in its final packaging alongside control samples under real-world and accelerated storage conditions (room temperature, elevated temperature, cooling, and freeze-thaw thermal cycles).

Test duration depends on expected shelf life and accelerated aging models. Evaluations are performed at baseline and predetermined time points.

Acceptance criteria should establish limits for:

• Changes in weight, pH, viscosity, color, and scent
• Leak-tightness, visual appearance, and mechanical durability
• Dispenser, pump, and closure functionality
• Migrating substances passing into the formulation (or vice versa)

Parallel stability studies monitor physicochemical parameters and seal integrity. Seal tightness can be evaluated using weight loss monitoring, vacuum decay tests, leak inspections, or gas/moisture permeability measurements, tailored to the specific container design.

Supply Chain Compliance and Managing Changes

Suppliers must provide comprehensive material specifications, additive disclosures, declarations of conformity, and relevant test reports tailored to the exact model, color variant, and material grade.

Any modification to raw materials, pigments, gaskets, manufacturing processes, or sub-suppliers requires a re-evaluation of compliance. The same applies when reformulating the cosmetic, even if the container remains unchanged.

Simply receiving a supplier declaration is not enough; brand owners must verify which material grade the document covers, which standards were applied, and whether test conditions match actual product exposure. Ultimate legal responsibility for product safety lies with the designated Responsible Person placing the cosmetic on the EU market.