Sterile medical devices: a long production process

Medical devices designed to arrive at the market presterilized require separate steps in production. Depending on the product, this can mean that sterilization occurs during the final manufacturing step or may require cleanroom production. The sterilization methods differ and depend on the nature of the product.

A cleanroom is a controlled environment where pollutants like airborne microbes, and aerosol particles are filtered out to stop them from settling on medical devices or semiconductor products, for example. Medical research often uses cleanroom environments. These facilities enable specialized production of products such as sterile wound dressings, implant devices, structural components, and complete devices.

Cleanrooms are subject to a range of classifications and standards based on their capabilities and intended applications. For example, the International Organization for Standardization, ISO 14644-1, and ISO 14644-2 are used in semiconductor manufacturing. The EU-GMP Guide Annex 1 (Manufacture of Sterile Medicinal Products) applies to the sterile production of pharmaceutical products.

Sterile manufacturing may not always be possible

Manufacturers try to keep products completely free of microbiological contamination. Sometimes the final step of production involves the sterilization of already-packaged products. This final sterilization step is needed to remove pathogenic microorganisms and particles from many plastic patient-care items. The highest level of purity is maintained in the above-mentioned cleanrooms along the entire manufacturing process. Even so, this does not mean that the products remain completely sterile throughout this process. Sterilization as a final product step is still a necessity if the products receive subsequent treatment and are touched by people or come into contact with ambient air, for example. It is certainly ideal if plastic products made from injection molding are immediately enclosed in sterile packaging since they are already ejected in sterile condition thanks to the high temperatures. This can shorten subsequent steps such as packaging and sterilization. Some manufacturers already implement this process. However, due to logistical and cost reasons, many manufacturers are forced to pass these production steps on to other service providers.

Proper sterilization packaging

If sterile packaging is not an option for medical devices immediately after production, they must be sterilized in the packaging during a final production step. This can be done by the manufacturer or can be contracted out to an external sterilization provider. There are a variety of methods, including radiation or ethylene oxide sterilization systems. In an interview, Patrick Radermacher, CEO of industrial equipment supplier STERYSIS, tells us why ethylene oxide is a great sterilization agent for plastic products: "Ethylene oxide is product neutral. This involves a so-called cold sterilization process, which makes it ideal for plastic products because it is hard to imagine steam sterilization at 130 degrees Celsius for these types of items. Ethylene oxide is superior to other approaches in terms of material compatibility." (Click here for the full interview). Medical devices made of plastic are sterilized using ethylene oxide in overpressure or vacuum sterilization systems. The choice of method depends on the number of products that must be sterilized.

In contrast, the radiation-based method (gamma or beta radiation) can sterilize many products made from other materials. Products are packaged in crates or on pallets and quickly and cleanly passed through the radiation source in big chambers or on assembly lines. The choice of method depends on the product. Watch this video to find out how BGS sterilizes its products.