Shaping the silicone dream31 October 2017
More and more contract manufacturers are turning to silicone-based materials to sculpt the products they need to deliver for a variety of uses in the medical devices field. Medical Device Developments explains how, with the aid of API manufacturing processes, silicone can cut down times and complications in the manufacturing schemes of many outsourcing partners for OEMs.
As the industry behemoth Dow Corning puts it, “the siliconemanufacturing process sounds simple,” deceptively so, even. “Take silicon, methyl chloride, and a dash of catalyst. Heat. Add water. And out pops an infinite assortment of silicone fluids, elastomers, gels and resins,” it says. But with that simple process comes many varieties – and many changes in cost.
But with this process, silicone can be used extensively in moulding and tubing for a variety of processes to help machine functions, maximise profits and even simplify the production process for LSR injection moulding.
Silicones are used today in many devices that are essential to modern medicine, such as pacemakers or hydrocephalic shunts. Silicones are also used in many other medical capacities, most notably in pharmaceutical applications, from process aids like tubing used to manufacture pharmaceuticals, to excipients in topical formulations or adhesives to affix transdermal drug delivery systems.
The product is durable and versatile, and is now one of the most used in the medical sector. But in today’s complicated world of manufacturing, it’s never that simple, especially when it comes to contract manufacturing. And one of the main ways this occurs is in contract manufacturers providing custom silicone-moulded products for the medical devices industry and other applications.
The new normal
There are many factors and technologies that are causing manufacturers to outsource their injection-moulding needs. One of the main reasons is that the medical moulding market is in a near-constant state of change, as technology and market pressures drive companies to seek new deals. As the industry news website medicalproductoutsourcing.com puts it, this means that “moulding providers must keep up with these changes to stay ahead of what OEMs are seeking today and tomorrow”.
The website says one clear area that is changing rapidly is the move to consolidate services. This desire to consolidate means that the commercial landscape “is constantly being altered”, from OEMs working with multiple smallcontract shops to complete moulding services through to working with much larger operations.
“Simultaneously, some OEMs still prefer to work with services in their location, so many large moulding service companies are answering this need by opening up more regional divisions,” says Joyce Laird from Medical Product Outsourcing.
What this means is that the constant changes are having an effect on OEMs baselines. The industry itself is going through such enormous cultural change in the ways it monitors and manages its manufacturing processes, that many companies are trying to have their cake and eat it too. OEMs are trying to use big and small moulding outsourcing providers, as well as manage budgets and embrace new technology.
Contract manufacturers are also affected by this and are, in fact, losing out with the constant changes. It can become too expensive to be constantly at the whim of a large OEM, even though they are being driven by valid financial concerns. Products like silicone – which can be used by all companies, have a simple manufacturing process and good commercial saleability – are therefore an easy bet.
So could silicone provide a slightly more stable way of going about this process? It’s easy to use, cheap and has many other benefits over more traditional materials that have long been more popular. But what is the truth?
The world of silicone
At the Silicone World Summit that takes place every year in November – this year in Munich – the speakers showcased a wide variety of new tech and R&D in the world of silicone. While it may not be the sexiest thing you’ll ever listen to, it will bring a higher level of convenience and efficiency to the process.
Dr Markus Putzer, global technology leader for elastomers, and technology site leader of American manufacturer Momentive Performance Materials, opened the summit with a discussion on ‘The world-record of silicones: Innovations powered by a unique elastomers’. He spoke about how the unique features of silicone represent a new world of technology for medical devices that the industry must wake up to.
Other topics discussed included the advancements in adhesion of fluorinated liquid silicone rubber to substrates, the extrusion process of high-consistency silicone rubber and achieving optimal process parameters for elastomeric applications by virtual moulding. All this goes to show just how much silicone is being relied on by high-tech, innovative companies in their new solutions.
While most contract-design and development services are designed to enable manufacturers or supplier to bring products to market more quickly and efficiently than is possible with their own resources, there are always going to be problems. The design and development teams that work in these field business unit specialise in delivery systems and associated products for minimally and less-invasive therapies.
The entire process of contract manufacturing, as an outsourcing of certain production activities that were previously performed by the manufacturer to a third party, means that, from the initial engagement, the focus is always on ways to add value to the development needs of the project and how to use the expertise of contract manufacturers to save money for all involved. So how is it using this product and what can it offer?
The benefits of the products are known throughout the industry. An industry focus piece in Plastics Technology magazine in May 2017 put it best when editor Jim Callari noted that “combining silicone products with an API provides a variety of benefits. For one, it can permit a more controlled release rate of the medicine. Secondly, it allows a more targeted delivery of the API.”
Many refer to APIs as bulk pharmaceuticals and they are, in fact, usually manufactured separately from tablets, suspensions and liquids. The greatest concentrations of API manufacturers are located around Asia, specifically in India and China. The benefits experienced in outsourcing of pharma processes can also be found in medical device manufacturing.
While this means costs are lower and more competitive for the big Western manufacturing firms, and has led to more companies outsourcing API manufacturing, it has also eliminated the need to invest in expensive equipment and infrastructure. On top of everything such as regulatory issues and the troubles of finding and keeping reliable working relationships, equipment can also be complicated to install and maintain.
According to the Active Pharmaceutical Ingredient Manufacturing (APIM) API Industry Guide lists, these processes can be found with pharma company AstraZeneca, which manufactures 85% of its APIs but is currently in the process of withdrawing from all API production in favour of outsourcing.
What does this have to do with silicone? The answer is more complex. APIM, in conversation with Drew Rogers, global director of healthcare and medical for engineering company Trelleborg Sealing Solutions, discussed how API and other factors are changing the production of silicone. “Silicone products and drugs can be combined in one of three ways,” Rogers explained. “In one scenario, raw silicone and a powdered form of a drug are mixed prior to fabrication. The drawback of this technique is that silicone is typically cured at high temperatures and the extreme heat can affect the efficacy of the medicine.”
While the changes the product can suffer through is not changing, the way it is manufactured is, and that’s key. Silicone and its associated materials have already been used in medical materials and device manufacturing for over six decades. “Quickly after their commercial availability in 1946, methylchlorosilanes were described to treat glassware to prevent blood from clotting,” said a conference report from Dow Corning. At the same time as these breakthroughs were happening, a Dr F Lahey implanted a silicone elastomer tube for duct repair in surgery on the bile ducts. “Since these pioneers, the interest for silicones in medical applications has remained because of their recognised biocompatibility,” the report said.
Contract manufacturers and silicone
Dow Corning’s global strategic marketing manager, Gary Lord, said in a 2016 interview that the medical device industry was looking to maximise the solutions that they could get from suppliers and they wanted – and needed – innovation. “We need innovation with materials that have a good proven performance and a long history in terms of their use,” he said. But he added they also needed to be able to put them together in new and innovative ways. “That’s what, for me, is the exciting opportunity to be out here, bringing the silicone chemistry industry and blending that with the organic chemistry that they have.”
They can start by looking at different types of adhesives, such as plastics – and the mighty silicone – that many contract manufacturers will have expertise in, as well as carbon-based adhesives like acrylics. Plastics have rigid forms that many have struggled to come up with because they need more flexibility. “I think the opportunities and the ability, if you will,” said Lord, “is to bring lots of different technologies, processing technologies as well as chemistries, together to innovate with our customer.”
In the past, feedback that was given from medical device OEMs was usually positive, but will that be so when silicone becomes the new normal? Most will want to know what’s coming in the future, and how the contract manufacturers will build on the collaboration between silicone and carbon base. “I think everybody’s waiting to see what comes from that and what will be put together next,” Lord said.
Here are the best tips for using silicone; Mark Hammond, general manager at GW Silicones Royalton, writing on medicaldesign.com, lists the best thing to do with silicone as material selection. “Materials have greatly improved over the past ten years,” he says. “It doesn’t make sense to rely only on familiar materials and potentially overlook performance gains, processing stability and lower prices. The latest LSRs have improved upon original formulations and have closed the gap on the mechanical properties of high-consistency silicone (HCR), a material [that is] typically compression or transfer-moulded. LSRs can provide a better choice than HCRs because their platinum cure system takes significantly shorter cure times.”
What this means is think outside the box and look to new products for the best value. Other tips are to choose the best vendor with your eyes open. “Because of a lack of expertise in silicone at the OEM level, many moulding programmes are sourced based on an internet search, a past relationship, or what company is closest or cheapest. But just because a company owns a silicone machine does not make it a qualified and experienced silicone moulder,” he says.
Hammond’s third tip is to be careful with prototypes and production tooling. “A high-quality silicone mould at the beginning of a project may seem like a large out-of-pocket expense, but the investment will pay for itself many times over during the life of the programme in piece, price and part consistency,” says Hammond. And finally, embrace technology. The world of silicone is changing. And OEMs and contract manufacturers must respect that what was current or cost-effective five years ago is no longer. Silicone could be a great positive for medical devices, or it could be just another tool. The difference is how you use it.