Adam Howard, director, Seals Direct, explains the difference between silicone and medical grade silicone, and provides examples of how it is used within the medical industry.
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Medical grade silicone rubber is a specialised type of silicone that meets the biocompatibility and safety standards set by regulatory bodies like the FDA and ISO. It is formulated for use in medical applications where contact with human tissue, blood and other bodily fluids may occur. This material is known for its purity, flexibility, durability and resistance to extreme temperatures.
How does silicone rubber differ to medical grade silicone rubber?
Medical grade silicone often differs from commercial silicone in several significant ways. These differences are primarily related to the compounds purity, biocompatibility, regulatory approval and sterilisation capabilities. Medical grade silicone is often purer than other grades of silicone and is manufactured under stricter controls to ensure the elimination of contaminants that could potentially cause adverse reactions when in contact with human tissue. This high level of purity is essential to ensure suitability in sensitive medical applications.
Another key difference lies in the compounds biocompatibility. Medical grade silicone rubber undergoes rigorous testing to ensure it is compatible with human tissues and fluids. This testing guarantees that the material does not cause irritation, toxicity or allergic reactions to confirm it safe for use in direct contact with the human body. This compares to other silicone rubber compounds that may not meet these biocompatibility standards and are therefore unsuitable for many medical applications such as contact with human tissue.
Regulatory approval is another factor that distinguishes medical grade silicone rubber from other grades. It must comply with the regulations set by health authorities such as the FDA and ISO to ensure that it meets the highest standards of safety and efficacy for medical use. Standard silicone rubber, while widely used in other industries, does not always meet these specific regulatory requirements.
Medical grade silicone is also designed to withstand various methods of sterilisation, including autoclaving, gamma irradiation and ethylene oxide sterilisation, without degrading. This property is important for maintaining the materials integrity whilst ensuring it remains safe for repeated medical use. Other silicone compounds may not possess the same level of resistance to these sterilisation processes which could limit their suitability for medical applications where sterilisation is essential.
How does the medical industry use silicone rubber?
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The medical industry uses medical grade silicone rubber in a wide array of applications due to its versatility and biocompatibility. One of the primary uses of this material is in implants, including pacemakers, hydrocephalus shunts and breast implants. Its biocompatibility and durability make it ideal for long-term implantation in the human body. Silicone rubber is also extensively used in the production of catheters and tubing which are essential components in various medical procedures for fluid transfer and drainage.
Additionally, surgical instruments and tools often feature silicone rubber in their handles and grips. This material can provide ergonomic benefits that enhance the comfort and precision of surgical procedures.
Medical grade silicone rubber also plays an important role in drug delivery systems. This material is used in controlled release drug delivery mechanisms, such as transdermal patches and implantable devices, where its stability and biocompatibility ensure effective and safe medication administration. Silicone rubber also has gentle adhesion properties and non-irritating nature so is beneficial in wound care products such as dressings. These features make it an ideal material for use on sensitive or compromised skin to promote healing whilst minimising discomfort.
Advantages of medical grade silicone rubber
This material offers several advantages which make it a preferred material in the healthcare industry. Although medical grade silicone offers a number of unique properties for medical applications, some of these benefits are shared with most silicone compounds which exhibit similar physical characteristics.
The main advantage of medical grade silicone is its compliance and accreditation from various regulatory bodies.
Medical silicone also offers biocompatibility. This means that it is highly compatible with human tissues and fluids and can reduce the risk of adverse reactions such as irritation, toxicity or allergic responses. This property is important for medical applications that involve direct contact with the human body, such as implants, catheters and wound care products.
Another advantage of most silicone compounds is its durability. Silicone rubber exhibits a resistance to wear and tear and extreme temperatures, which ensures its long-lasting performance in various medical applications. Whether used in an implant or a prosthetic device, silicone rubber maintains its integrity and functionality over extended periods to provide reliable and consistent results.
Flexibility is another physical benefit of most silicone compounds. It retains its flexibility and elasticity over a wide range of temperatures so is suitable for dynamic applications that require the material to bend, stretch and move without breaking. This flexibility is particularly valuable in applications such as tubing, catheters, and surgical instruments, where adaptability is essential for both functionality and patient comfort.
Most silicone compounds can be manufactured in a wide variety of colours. This also includes transparent compounds which can be an advantage in specific applications, such as in tubing and certain implants. This transparency allows for visual monitoring of fluid flow and other internal processes to provide an additional layer of functionality that enhances patient care and treatment outcomes.
Disadvantages of medical grade silicone rubber
Despite its many advantages, medical grade silicone rubber also has some limitations that should be considered when choosing the best compound for your application. One of the primary disadvantages is its cost. The stringent manufacturing processes, additional testing and regulatory compliance required for medical grade silicone significantly increases its production costs compared to standard silicone rubber. This higher cost can be a limiting factor, especially in applications where budget constraints are a concern.
Another limitation is related to its mechanical properties. While medical grade silicone rubber is durable and flexible, it may not have the same mechanical strength as some other materials such as EPDM or Neoprene. This can restrict its use in applications that require high tensile strength and resistance to heavy loads or high-impact forces. In such cases, alternative materials that offer superior mechanical properties might be preferred.
The permeability of silicone rubber to certain gases and liquids is another potential drawback. This permeability can make it unsuitable for some medical applications where a completely impermeable barrier is required. For instance, in certain drug delivery systems or implants, the permeation of external substances could affect the efficacy and safety of the device.
Additionally, the processing and moulding of medical grade silicone rubber can be more complex than other materials. Specialised equipment and expertise are often required to work with silicone, which can increase production time and costs. This complexity can be a barrier for some manufacturers such as those without the necessary infrastructure or experience in handling medical grade materials.