TPI May 2021

Silicone tubing: applications in the pharmaceutical setting and the global fight against Covid-19

By Matthew Bishop, operations manager at Viking Extrusions

Silicone tubing is very popular across the medical and pharmaceutical industries, and the material itself is present in virtually every medicinal environment. There are practical as well as economical reasons for this. Tubes made from silicone are chemically inert and FDA approved, and allow for the easy transportation of both gases and liquids. An important example of silicone tubing in a medical sense are peristaltic pumps. These pumps are vital for functioning ventilators, the same kind that we are all too familiar with. They are the ventilators that aid with assisted breathing, and have been particularly newsworthy recently because of the coronavirus pandemic. There was

In the case of peroxide-cured silicone, the excess peroxide is burnt off in a long post-cure. It is still as efficient but for convenience more people tend to favour the platinum-cured variant. The importance of cleanliness Silicone is not just used in the pharmaceutical setting. The same qualities that make it useful for medicinal purposes – the ease of which it can be sterilised and its robustness – also make it useful for the food processing industry.

The silicone tubing allows for the easy transportation of both gases and liquids

The fact that silicone tubing is FDA approved means it can be applied virtually anywhere a production line needs to carry liquids that may be consumed. Or where the tubing will be exposed to extremely high or low temperatures. For example, platinum-cured tubing is used extensively in the dairy industry on milking machines. With both food and pharmaceutical production, the sensitivity-requirements of the silicone are similar. Extra care must be taken to ensure that there is no contamination from any other material grades, thus ensuring a very clean environment. Likewise, extra attention and care also has to be directed towards the handling of the parts to make sure they are sterile. Unsung heroes? Most people probably attribute silicone to DIY sealants and adhesives and nothing else. But the tubing that we are increasingly reliant on is almost universally used to help satisfy production lines all over the food and pharmaceutical world. And as we have seen, they were sorely needed back in March, when governments began to universally plan for an overwhelming viral run on the hospitals. Given the impact of the coronavirus and the surge in demand of ventilators at the beginning of the lockdown, I expect the market will pay more attention to – and insist on – ever more refined silicone grades, and especially in pharmaceuticals. We are at the beginning of a new age of silicone extrusion production.

an unprecedented demand for silicone peristaltic pumps and other types of ventilator tubing made from silicone shortly after the coronavirus outbreak. And though the demand for peristaltic pumps has levelled out now, there is still a lot of interest in the different types of silicone medical tubing, for the development and deliverance of medical goods to meet the surge in response to the outbreak. Medical grade silicone tubing will be used in much of the equipment that will be used to make a vaccine. Silicone and sterilisation Silicone has been a popular go-to material since the mid- twentieth century, and has competed with PVC and various other types of plastic and rubber tubing. But at least in a medical sense, silicone has an advantage over many of these other materials in that it is heat resistant to a higher temperature than most other translucent materials – such as plastics – making it safer. In fact, silicone can resist extreme high and low temperatures. Ranging from -60°C to temperatures exceeding 200°C. (And higher grades are available to withstand even greater temperatures.) This temperature robustness is largely down to the chemical stability that silicone exhibits, and makes it particularly useful for piping and tubing that needs to be sterilised — that is, heated up to the point where any microbes are destroyed, without damage to the tube itself. The different types of silicone tubing There are two popular types of silicone that are licensed for medical applications: peroxide-cured and platinum-cured. The latter grade is usually preferred over the latter because it has a particularly high tear strength for extra robustness. Platinum-cured silicone can also undergo what’s known as an “addition cured” process, meaning no chemicals can come off of it. A very important quality that ensures purity of whatever substance is passing through the tube.

Viking Extrusions www.vikingextrusions.co.uk

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May 2021 TUBE PRODUCTS INTERNATIONAL