According to ISO10993/GB16886, enterprises need to carry out biological evaluation of medical devices to ensure the safety of medical devices in the use. As the first step of biological evaluation, material chemical characterization provides the necessary data support for the safety evaluation.

ISO10993-1: 2018 further clarifies the importance of chemical characterization of materials. Biological evaluation of medical devices focuses on minimizing the number and exposure of test animals by giving preference to in vitro models and to chemical, physical, morphological, and topographical characterization testing. Obtaining physical/chemical information and considering material characterization are prerequisite information needed for a risk assessment, taking precedence over any biological experiments. 

In some cases, additional chemical information may be required, and chemical characterization and toxicological information may have to be used to support risk assessment, such as unexpected results observed in biocompatibility tests, devices containing known toxic chemicals (such as drugs in drug combinations), devices made of degradable, absorbent materials, etc.

Compatibility between medical devices and drugs is a very important part of safety evaluation of medical devices. Enterprises need to identify potential risks in the process of contact between materials and human body, conduct necessary analysis and testing for potential risks and make corresponding risk assessment. In the Guidelines for Technical Review of Registration of Disposable Infusion Devices issued by CMDE of NMPA, it is clearly pointed out that "For the devices expected to be used for infusion of drugs, enterprises need to submit a compatibility study report of the infused drugs and devices". At the same time, medical device products such as medical combination products and medical nebulizers, which are expected to be in contact with drugs or blood, should carry out corresponding compatibility studies during the safety evaluation research.

Compatibility study of medical devices and drugs mainly includes three parts: a) adsorption study, b) leachable substance study - known substance, c) leachable substance study - unknown substance. Compatibility research of medical devices is very challenging. It requires not only professional technicians to accurately identify potential leachate, but also professional instruments to quantitatively study potential leachables, so as to provide reliable data support for safety evaluation of medical devices.

Material used for making instruments may produce degradation products in biological environment, which may show different roles in the body as the main material. These degradation products may or may not react with the biological environment, but the accumulation of a large number of stable degradation products may have physical effects on surrounding tissues, or may migrate in the biological environment. Bioacceptability of degradation products depends on their properties and concentration, so the study of degradation products should be considered in risk management of some devices.
Consideration should be given to the study of degradation products, including:
1）Medical device designed to be bio-absorbent.
2）End products of medical devices are recognized as releasing toxic degradation substances during human exposure.
The basic framework of qualitative and quantitative analysis of degradation products is given in GB/T 16886.9 & ISO 10993-9. GB/T 16886.13 & ISO 10993-13, GB/T 16886.14 & ISO 10993-14 and GB/T 16886.15 & ISO 10993-15 described in vitro degradation tests of polymers, ceramics and metals, respectively.

In order to reduce the time and cost of product development and ensure the safe and effective products to be successfully marketed, it is necessary for medical enterprises to study the clinical appliances in the process of medical device development and design. At the same time, the properties of materials expected to be used in products should be studied and evaluated.

With the help of powerful analysis and testing platform and technical ability, we provide analysis and testing services for medical polymer materials, metal and alloy materials and other materials used in various devices, and help to improve the technical ability and efficiency of enterprise products in the development, design, quality management and other links. Our services include: material composition analysis, qualitative and quantitative analysis of additives and processing aids, elemental testing, purity content testing and physical and chemical properties testing.

Pollutants and residues in the process are one of the important factors affecting the safety of medical devices, so it is very important to consider the influence of material processing conditions and the use and pollution of additives. Special consideration should be given to:

1. Process contaminants such as moulding, surface treatment, welding or machining;
2. Expected additives or processing aids, such as catalysts, antioxidants, surface treatment agents and others;
3. Potential process pollutants, such as cleaning agents, disinfectants/sterilizers, etchants, release agents, cutting fluids, lubricants, etc;
4. Degradation products during production and processing, clinical use and storage;
5. Potential chemicals and residues of additives.

The leachable substance of contact devices is an important research object in risk assessment of medical devices. It should be managed by identifying leachable substances, quantifying leachable substances at risk and establishing a limited amount of exposure. ISO 10993 provides a method for calculating allowable limits of leachable substances by using health risk data. In practice, researchers are required to calculate toxicological data and evaluate the risk of equipment products according to the actual situation of equipment products.