Amira Fernandez Ramos, AIMPLAS, discusses how studies showed an increase in the production of medical devices in 2021, especially disposable medical devices.
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Since then, R&D on new medical technologies and growing demand for diagnostic and prevention devices have led to increased production of medical devices (MDs). Due to the expanding presence of these products, it is essential to clarify the requirements to improve manufacturing, ensure consumer and patient safety, and respond to market needs.
In this context, Regulation (EU) 2017/745 on medical devices, which repeals Council Directives 90/385/EEC and 93/42/EEC, defines the products covered, provides the essential requirements that must be fulfilled by medical devices and accessories, and describes the conformity assessment procedure that manufacturers must apply to ensure compliance with essential requirements.
Medical devices: Definition
According to Article 2 of Regulation (EU) 2017/745, medical devices can be any instrument, apparatus, appliance, software, implant, reagent, material or other article intended by the manufacturer to be used for human beings for one or more of the following specific medical purposes:
- diagnosis, prevention, monitoring, prediction, prognosis, treatment or alleviation of disease,
- diagnosis, monitoring, treatment, alleviation of, or compensation for, an injury or disability,
- investigation, replacement or modification of the anatomy or of a physiological or pathological process or state,
- providing information by means of in vitro examination of specimens derived from the human body, including organ, blood and tissue donations,
and which does not achieve its principal intended action by pharmacological, immunological or metabolic means, in or on the human body, but which may be assisted in its function by such means.
Devices for the control or support of conception and products specifically intended for the cleaning, disinfection or sterilisation of devices are also deemed to be medical devices.
Regulation on medical devices: Requirements for medical devices
For equipment, devices and related accessories, the Regulation on Medical Devices includes some essential requirements:
- The equipment should be safe and the risk should be within acceptable limits;
- The device should be designed according to the state of the art and any risks should be eliminated or prevented; otherwise, a warning should be provided;
- The equipment should meet the manufacturer’s specified performance requirements;
- The safety and performance of the device should be guaranteed within the lifetime of the device;
- The safety and performance of the device should not be affected under reasonable transport and storage conditions;
- The adverse effects and benefits of the device should be within acceptable limits.
In addition to these criteria, it is also important to consider the health requirements of a medical device. To ensure MD safety, it is important to assess the biological response to the MD. To meet these requirements, different tests should be designed and carried out to evaluate the MD’s biocompatibility. When preclinical testing is complete, the MD can be considered safe and earns the CE marking.
Risk assessment and biocompatibility of medical devices
To respond to these needs, ISO 10993 describes the safety standards for evaluating the biocompatibility of medical devices. According to the standard, biocompatibility is the ability of a medical device or material to perform with an appropriate host response in a specific application. This description includes the materials (and their degradation products, leachables and residuals) that make up a medical device that is intended to be used for contact with or in the human body and does not have a negative impact on the patient or consumer’s health.
It is important to have a thorough understanding of the MD and its application before starting a risk assessment procedure. This understanding should include the nature, degree, duration, frequency and conditions of exposure to or contact with humans. Moreover, ISO 10993 and subsequent FDA guidance emphasize that the risk assessment should evaluate the MD in its final finished form. If this is not possible, a representative test article of all materials and processing steps (manufacturing, sterilization, storage, etc.) may be considered. Device components requiring biological evaluation include the following:
- The construction material(s);
- Intended additives, process contaminants and residuals;
- Packaging materials;
- Leachable substances;
- Degradation products.
One of the requirements of risk assessment is identification and characterization of the materials that make up the MD. ISO 10993 describes the tests, requirements and conditions that must be applied for device characterization, taking into account the characteristics mentioned above. In this context, manufacturers need to know the key parts of the standard:
- Chemical, physical and mechanical characterization: ISO 10993-18 and 19;
- Identification and quantification of the degradation products of polymers and ceramic and metal products: ISO 10993-9, 13, 14, 15;
- Determination of ethylene oxide residuals: ISO 10993-7
The biocompatibility testing for assessing the toxicity of a medical device is described in detail in different chapters of the ISO 10993 standard. The biological testing described in ISO 10993 includes cytotoxicity (ISO 10993-5), skin sensibilisation (ISO 10993-10), skin, eye and mucosal irritation (ISO 10993-10), intracutaneous reactivity (ISO 10993-10), systemic and subchronic toxicity (ISO 10993-11), genotoxicity (ISO 10993-3) and blood compatibility (ISO 10993-4).
ISO 10993-1 does not establish a specific battery of tests for particular MDs. Instead, it provides a framework that can be used to design a biocompatibility testing plan. MD manufacturers should consult an experienced laboratory to determine the best way to fulfil material biocompatibility requirements. Biocompatibility testing should always be conducted in compliance with ISO/IEC 17025 and/or Principles of Good Laboratory Practice (GLP).
MD manufacturers should collect safety data on each component and material used in a device. Testing of the finished device should also be conducted as specified by ISO 10993-1. In general, the best approach is to:
- collect supplier data on potential materials.
- perform analytical and in vitro screening of materials.
- perform confirmatory testing on a test article of the final finished device.
There is a risk involved in testing the finished MD without collecting data on its component materials. If an adverse effect occurs, it can be difficult to trace the component responsible for the concern. Regulatory submissions may be delayed due to the need to repeat tests on individual components.
Screening the device materials helps minimise this risk. Chemical characterisation can detect leachable substances that could compromise MD safety. Inexpensive non-animal methods such as cytotoxicity tests provide an additional screening method for material safety. Screening can thus make it unnecessary to redesign the MD due to biocompatibility testing failures.