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Seven Tips for Selecting Medical Device Seals

By CRGI on

medical device sealsMedical devices are critical assets that are used extensively in the delivery of healthcare services. Because such devices are a key element in the overall patient experience and the quality, safety and effectiveness of the healthcare service delivered, selecting the right seal is critical for device performance and patient safety.

A medical device is used to diagnose, prevent, or treat a medical disease or condition without having any chemical action on any part of the body. The US FDA recognizes three classes of medical devices. Class 1 devices are low risk devices, including handheld surgical instruments, non-electric wheelchairs, and the like. Class II devices are intermediate-risk devices, including CT and MRI scanners, infusion pumps for intravenous medications, etc. Class III devices are high-risk devices that are very important to health or sustaining life. Examples include pacemakers and deep-brain stimulators.

The importance of medical device seals

Seals and gaskets are an integral part of many medical devices, irrespective of class. In a wide range of devices, from syringes and infusion pumps to surgical power tools and CT scanners, these seals protect patients and healthcare personnel by keeping devices free from harmful contaminants and leakage while ensuring reliable and consistent performance.

In many medical devices, seals are a critical operating component. When a seal fails, or fails to perform adequately, the consequences can be significant. For example, an electric wheelchair can go out of control when a seal fails to block electromagnetic interference (EMI) from a nearby cell phone. A seal failure on an infusion pump can result in the over- or under-dosing of a patient with a needed drug. For these reasons, selecting the right sealing solution is a key aspect of the design, manufacture, and maintenance of a medical device. In this blog we present some helpful tips for ensuring that the right seal is chosen.

Tips for selecting medical device seals

Tip #1: Understand all the application requirements to ensure the right material is selected. When choosing a seal for a medical device, be sure to understand all the physical application requirements. These include such things as hardware specifications, media contact (medical device seals are often exposed to aggressive and harsh chemicals and fluids), motion, temperature, pressure and vacuum, and the required life of the seal. Understanding the full range of application requirements is key for ensuring the right sealing material is selected, ensuring the finished seal has the required performance, reliability, and durability.

Tip #2: Consider regulatory compliance. Depending upon the application, some sealing materials may require USP Class VI certification. Similarly, to assure quality and compliance with regulations, a medical device OEM may want the choose a seal supplier whose operations are carried out in a facility which has the appropriate certifications.

Tip #3: Evaluate and consider biocompatibility. Depending upon the application, a medical device seal may come into contact with living tissue, bodily fluids, drugs, etc. In these cases, it is necessary to consider the degree to which a sealing material can come into contact with a living system without producing an adverse effect.

Tip #4: Consider the need for sterilization. Seals placed into devices which require sterilization can be exposed to radiation or high temperatures, depending upon whether radiation or autoclave sterilization is used. The choice of sterilization can affect material selection. For example, while PTFE seals exhibits average performance in autoclave sterilization, these seals do not hold up well when exposed to gamma radiation.

Tip #5: Consider the need to shield against EMI. Medical devices may need to be shielded against the effects of EMI, as this can degrade or disrupt their operation and performance. The outer enclosure of a medical device will often have openings through which cables, tubes, etc. must pass. These openings, as well as the overall housing, may need to be sealed with EMI shielding gaskets to protect the device against the effects of EMI.

Tip #6: Consider the material grade needed to support the application. Some material grades widely used for industrial sealing solutions are not appropriate for medical device applications. An example is nitrile rubber, a material widely used to produce industrial O-rings. This material is increasingly being banned from use in medical devices as it can fail when exposed to ozone and may be compounded with dioctyl or diisononyl phthalates that could be harmful to human health. Where possible, medical-grade rubbers should always be chosen for medical device seals.

Tip #7: Qualify two materials to reduce the risk of discontinuance or modification of a compound’s formula. Selecting only one material for a medical device seal exposes you to the risk of the compound being changed or discontinued by the material supplier. Qualifying two materials at the outset eliminates the need to requalify a material should this occur.

CRG can supply custom cut or molded medical device seals. Depending upon the application, these seals are made from a range of materials, including silicone rubber, fluoroelastomer (FKM or Viton®), EPDM, PTFE, conductive and non-conductive rubbers for EMI shielding, and others. Medical device OEM’s can count on CRG for guidance on material selection for their sealing application. Our team will guide all aspects of production, including prototyping, testing, and final part manufacture. To find out more about how CRG can assist with your medical device sealing needs, please contact our sales team at crg@canadarubbergroup.com.