For over 60 years, medical-grade silicones have been used within the healthcare industry. Originally used to coat glassware, both the pharmaceutical and medical device industry now utilise medical-grade silicones in everything from orthotics and prosthetics, to wound care and drug eluting devices. 

Because medical-grade silicone Heat Cure Rubber (HCR) is easily extrudable, inert and remains stable under different conditions, it is an ideal choice for the manufacture of tubing for pharmaceutical processing based on living organisms, also called bioprocessing. 

Additionally, medical-grade silicone is hydrophobic and bacteria resistant. These properties, alongside being soft to the touch and conformable, means that medical-grade silicone is also ideal for implantable devices. Whether applied on or under the skin, silicone’s biocompatible material ensures it is safe to use in long-term implants such as drug eluting devices and catheters. 

Using medical grade silicones for biologics production: fluid transfer 

Globally, biologics are the fastest growing segment in the pharmaceutical industry. Biologic medicines are created by using living cells, with examples including gene and stem cell therapies and monoclonal antibodies. Offering high efficacy and innovative therapies, they are rapidly becoming indispensable in the treatment of chronic and complex diseases. Biologics have also been instrumental in the fight against the coronavirus. 

The demand for biologics is further fuelled by the increasing need for advanced drugs and treatments due to a growing elderly population, and the biologic outsourcing industry is experiencing increased regulatory approvals. According to GlobalData, sales of biologics are forecast to be $120bn greater than small molecule sales by 2027.  

Clément des Courières is regional market manager at Elkem Silicones, one of the world’s leading providers of advanced medical-grade silicones, and he tells us why silicone is so essential to the production of biologics. 

“Within bioprocessing, various tubing are used as components of Single-Use assemblies,” he explains. “These Single-Use systems have replaced the use of stainless steel in the synthesis of biological drugs, as they require a very sterile and inert environment. To transfer fluids from different parts of the process, tubing is used, and medical-grade silicone is the material of choice, being resistant to pressure and inherently elastic. Additionally, it can easily be sterilised so is ideal to be used in pumps to transfer fluids during the manufacturing process.” 

Medical-grade silicone tubing is made through extrusion, and Elkem provides extrusion-grade products that are produced in clean conditions. These materials are easy and efficient to extrude with no defects, says des Courières: 

“Within Heat Cure Rubber technologies, you have two main types, peroxide cure or platinum cures, and we offer both technologies as part of our Silbione™ brand.” 

High performance medical-grade silicones offer several key advantages: 

Thermal stability – Silicone tubing and assemblies are stable between temperatures of -80 °C to +215 °C 

High purity – Silicones possess a low extractables and leachables profile (which could interact with the process) making them perfect for pharma manufacturing processes. 

Easily sterilisable – Silicone tubing and assemblies can be sterilised through methods such as Gamma, Autoclave or ETO with little impact to the polymer’s performance. 

Proven performance – Silicones have been successfully used for more than 30 years in fluid transfer for pharma manufacturing. Additionally, biocompatibility of Silbione™ biomedical grade silicones is tested according to ISO 10993/USP Class VI procedures. 

Using medical-grade silicones for implants and catheters 

When it comes to implantable medical devices, such as catheters, medical-grade silicones are ideal as they are biocompatible, hypoallergenic and sterilisable. As catheters are tubes for fluid transfer that usually come into contact with human skin, they also need to be soft and comfortable for the patient. 

With low shrinkage, high resiliency, and cost-effective processing by extrusion, medical-grade heat cure rubber (HCR) is a popular choice for catheter tubing. Des Courières notes that although other materials are available, like PVC or thermoplastics, they contain plasticisers or residual monomers, raising safety concerns. 

“Medical-grade silicones are a proven technology, and it’s also here to stay – the technology of choice for the future,” he says. “They inherently have the softness without the need for plasticisers.” 

HCRs are ideal for making medical device parts, balloon catheters and extruded tubing. Elkem’s Silbione™ product line is widely used for producing high-quality parts for the healthcare market due to its easy milling and extrusion, good clarity, high mechanical strength, temperature resistance, and high-performance physical properties. 

Des Courières adds that as well as Elkem’s medical-grade silicone being based on a proven technology with over 60 years of history, Elkem’s global base can also be a benefit for their customers: 

“We are a global integrated company and have manufacturing sites for these ranges distributed around the world, so we can support our customers’ needs.” 

For more details of medical-grade silicone technologies, download the free paper below.