The Easiest Path to New Cosmetic Ingredient (NCI) Applications in China: A Case Study of Polymer Ingredients

Since the implementation of China's new cosmetics regulations, the application of NCIs has been in full swing. Currently, NCI registration and notification are divided into six distinct situations, each with its own set of requirements. These situations have different level of testing and documentation needed. Among these, polymer NCIs, categorized under Situation 6, are particularly popular due to their relatively straightforward application process. This article delves into why polymer ingredients are considered the easiest to apply for under the current regulatory framework, and outlines the specific requirements involved.

1. What Are Polymer Ingredients?

The definition of polymers in the cosmetics sector differs from that in the chemical industry. In the chemical industry, a polymer is broadly defined as a substance molecule composed of one or more monomer units sequenced together, with molecular weights distributed within a certain range. Molecular weights among polymers primarily depends on the number of monomer units within each polymer.

In the cosmetics sector, however, new polymer ingredients eligible for notification or registration under Situation 6 must be "chemically synthesized substances that are stable in structure and properties (excluding those with high biological activity), composed of one or more structural units linked by covalent bonds, with an average molecular weight exceeding 1,000 Daltons, and with the content of oligomers (molecules with a molecular weight below 1,000 Daltons) less than 10%." The average molecular weight and the oligomer content are key parameters, as they influence the ingredient's behavior and safety profile when applied to the skin.

Additionally, per China’s cosmetic regulations, single ingredient with clear chemical structures must meet specific purity requirements. For polymers, the purity or content must generally be at least 80%.

Below is a detailed comparison of the definition of polymer between cosmetic and chemical regulations.

2. Documentation Requirements for Polymer NCIs

The registration and notification process for polymer NCIs requires the submission of several key documents, including:

• Details of the registrant, notifier, and domestic responsible person, including name, address, and contact information.

• A research and development report of the new ingredient.

• Research documents on the preparation process, stability and quality control standards of the new ingredient.

• Safety assessment documents of the new ingredient.

3. Testing Requirements for Polymer NCIs

The application process for polymer NCIs has several key testing requirements, which can be grouped into three main categories:

a. Structure confirmation

During NCI registration and notification, NCIs with a clear chemical structure shall be submitted together with the chemical structure details, relative molecular mass, and relevant confirmation testing reports. For polymers, testing methods and results for the polymerization degree as well as the average molecular mass and its distribution shall also be submitted. Typical indicators and tests include:

• Chemical structure: Tests such as Nuclear Magnetic Resonance (NMR) spectroscopy, Infrared (IR) spectroscopy, Mass Spectrometry (MS), and Ultraviolet (UV) spectroscopy are used to confirm the chemical structure.

• Degree of polymerization, average molecular mass and its distribution: Tests like Gel Permeation Chromatography (GPC) and NMR are commonly employed to determine these parameters.

• Quality specification indexes, possible safety risk substances and their control, etc.: Attention should be given to by-products, starting materials, and solvents used in the polymer's synthesis, as these can introduce safety risks.

b. Toxicological Test

According to the Technical Guidelines for Cosmetic Safety Assessment 2021, chemically synthesized polymers generally do not require systemic toxicity and skin sensitization tests due to their large molecular weight, which prevents transdermal absorption. As a result, the toxicological tests required for polymer NCIs are limited to:

• Skin Irritation/Corrosion Test;

• Eye Irritation/Corrosion Test;

• Skin Phototoxicity Test (required only if the ingredient can absorb ultraviolet light).

These tests are significantly fewer compared to other types of NCIs, which makes the application process streamlined.

c. Stability test

Stability tests are mandatory for all NCIs, typically including destructive tests, accelerated tests, and long-term tests. Although existing cosmetics regulations do not provide specific guidelines for the key investigation items in polymer stability tests, chemical regulations can serve as a reference. These regulations suggest considering evaluating factors such as heat resistance, light resistance, oxidation resistance, water resistance, microbial resistance, and solvent resistance to assess the properties and performance of polymers.

4. Alternative Methods for Toxicological Tests of Polymers

For companies committed to ethical practices, polymer NCIs have a significant advantage of allowing for the complete avoidance of animal testing. Various in vitro methods validated by international organizations can be utilized to meet the toxicological testing requirements for polymers. These include: 

The selection of these methods should be based on the ingredient's structural characteristics. When necessary, an Integrated Approach to Testing and Assessment (IATA) can be employed to ensure comprehensive evaluation.

Moreover, according to the Provisions, if the animal testing alternative method used is not included in China's Safety and Technical Standards for Cosmetics (STSC), the alternative method shall be included by the international authoritative validation institution of alternative methods. Besides, the certification documents proving that the method can accurately predict the toxicological end point shall be submitted at the same time. The proof shall include a brief description of the research process of the alternative method, as well as the research data, result analysis, research conclusions, etc. of no less than 10 substances of known toxicity tested through the alternative method.

5. Status of Notified Polymers

As of the end of 2023, data from the NCI Notification Information System of the National Medical Products Administration (NMPA) revealed that a total of 117 NCIs had been notified, with 104 NCIs’ technical details published. Among these 104 NCIs, 26 were polymer NCIs, accounting for approximately 25% of the total. This significant proportion highlights the popularity and feasibility of polymer NCIs’ notification.

ChemLinked's parent company, REACH24H Consulting Group, has successfully assisted in the notification of eight polymer NCIs. Below are some of the cases. 

6. Conclusions

In conclusion, polymers represent the simplest type of ingredient in terms of NCI registration and notification in China. Their stability, lower safety risks, reduced testing requirements, and the possibility of avoiding animal testing make them an attractive option for companies seeking to bring new ingredients into the Chinese market quickly and efficiently.

With extensive compliance experience and expertise in polymer science, REACH24H Consulting Group offers a one-stop solution for polymer NCI notification. For more information and further support with polymer NCI application, please contact us at contact@chemlinked.com.