Germ warfare
Stephen Morley, Noxilizer looks at sterilisation tools for device designers and the way in which alternatives support innovation and improve manufacturing efficiency
Like many industries, the medical device industry is innovating to meet the requirements of a changing world. New technologies, materials and processes are continuously being introduced. This is driven by the need to improve patient safety, reduce production costs and optimise supply chain efficiency, and with that, reduce the cost of healthcare.
A growing proportion of drugs are bio-pharmaceuticals, which impose new constraints on packaging and processing due to being heat labile. There is also an increasing use of prefilled syringes (PFS). This is driven by both quality and cost factors, including greater fill and dosing accuracy (less waste, greater safety) and higher safety in self-administration (reduced cost, greater convenience).
Other examples of increasingly complex medical devices include drug-device combination products and customised implants, which create additional manufacturing and processing challenges.
As devices become more complex (eg. dual chamber syringes, drug-device combinations), the medley of materials grows, so do the challenges to successfully and efficiently sterilise them.
Sterilisation methods available for manufacturers include:
Steam
Despite high energy usage, steam sterilisation remains a simple and cost-effective method for materials that can withstand the temperature and pressure conditions. Steam/air autoclaves may be used in-house for a variety of medical and drug-delivery devices such as contact lenses and packaged prefilled syringes (heat-stable products). It is also non-toxic and leaves no residues.
Ethylene Oxide (EO)
Despite acknowledged pitfalls, EO remains the most widely-used method of sterilisation. It is compatible with a variety of materials (indeed, manufacturers of polymers have historically screened their materials for traditional sterilisation methods, so this broad compatibility is not surprising).
For drug-device combination products, there are concerns around toxic residuals, a relatively high temperature/humidity process and long ‘turnaround’ time (>20 days, including transportation). The main drawback to bringing EO sterilization in house is that it is flammable/explosive. Therefore, care must be taken when designing EO facilities, which generally require a dedicated building and systems to destroy the gas after use. These considerations require substantial investment, which, coupled with growing regulatory requirements have driven growth in the Sterilisation Service Provider segment.