Medical-grade Liquid Silicone Rubber (LSR) is becoming increasingly crucial to the medical device industry, as the combination of the general benefits of medical-grade silicones combine with LSR’s unique advantages for medical device OEMs. As new medical-grade LSR materials become commercially available, more reliable, better performing, and more affordable medical devices will be within reach of patients.

Medical-Grade Silicones

Silicone has long been a popular material for medical device manufacturers due to its durability, ease of molding by many methods, wide useful temperature range, chemical inertness, high tensile strength, vast range of available durometers, biocompatibility, and compatibility with many sterilization methods.

Medical-grade silicones add the benefits of stringent purity and biocompatibility testing, making them suitable for use in long-term implants.

One application where medical-grade silicones really shine is drug-eluting implantable devices. Before molding, silicones can be compounded with active pharmaceutical ingredients (APIs) such as cancer drugs or hormones which can can then be steadily released into a targeted area of the patient’s body over time once that molded implant is inserted.

Drug-eluting implants are able to maintain the desired level of the API in the patient much more consistently and over a longer period of time than both pills and injections. Also, since the implant can usually be inserted near the targeted organ or tissue, lower total amounts of API are needed because that API doesn’t need to spread throughout the entire body before reaching the targeted area.

As a result, the level of the API in the patient’s body remains inside the therapeutic window (the range of concentrations between too low to be effective and high enough to be toxic) for a much longer duration.

As we’ll see shortly, medical-grade LSR is a great material for making drug-eluting implants, due to its processing advantages.

The Advantages of LSR

LSR is a type of silicone material which starts out as two separate liquid components which are then precisely mixed together before injection into a heated mold, where the silicone elastomer becomes solid (i.e. vulcanizes).

The low viscosity of LSR makes it a great silicone material for making parts via injection molding, since the LSR can easily flow into and completely fill molds with relatively low injection pressures, even those with intricate and small features.

LSR’s inherent compatibility with injection molding results in the cost-effective, repeatable, and scalable manufacture of silicone parts—including medical devices and their components.

Furthermore, the temperatures needed to vulcanize LSR are usually low enough that significant degradation of compounded substances like APIs can be avoided. Thus, medical-grade LSR an excellent material for drug-eluting implants.

Implantables aren’t the only medical device application suitable for medical-grade LSR. Wearables (such as heart rate and activity monitors), respiratory products, linings for prosthetic limbs, and other devices which must stay in prolonged physical contact with a patient all benefit from medical-grade LSR’s outstanding biocompatibility and purity.

The Future of Medical-Grade LSRs

New and improved medical devices originate from innovations in both design and materials. As new medical-grade LSRs continue to be released on the market, the medical device industry as a whole will make steady advances and improve the length and quality of life of patients around the world.

Dow Corning’s release earlier this year of two new LSRs is a prime example. These new LSR materials cure quickly at low temperatures, don’t require a primer for binding to many substrates (including polyester), need low injection pressures, and boast broad process windows.

These are all significant features for the medical device industry for the following reasons:

  • Fast cure times at low vulcanizing temperatures enable silicone injection molders to shorten the total molding cycle time (which in turn can greatly reduce the cost per molded part), and consume less energy for each silicone part since the mold will not need to heated as much as other LSRs may require. Both of these result in reduce production costs for medical-grade LSR products, and consequently, lower costs for the patients and insurance companies to purchase these products.
  • The lower injection pressures of these LSRs will allow silicone medical device manufacturers to utilize more economical, lower tonnage injection presses. These LSRs’ broad process windows can enable lower defect and scrap rates, due to a more forgiving molding process.

New medical-grade LSRs, like these from Dow Corning, will help the whole medical device supply chain ramp up production capacity to meet global demand.

At ProMed, we combine industry-leading medical-grade LSR expertise with the latest developments in silicone materials and technology. From helping OEMs incorporate the latest medical-grade LSR formulations into their designs to delivering rapid silicone prototypes, we serve as a premier silicone molding contract manufacturer for medical device OEMs. Contact us to find out how we can help you.

The Importance of Medical-Grade Liquid Silicone Rubber
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The Importance of Medical-Grade Liquid Silicone Rubber
Medical-grade Liquid Silicone Rubber (LSR) is becoming increasingly crucial to the medical device industry, as the combination of the general benefits........
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ProMed Molding
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