Ahead of the annual Drug Delivery to the Lungs (DDL) conference, Senior Design Engineer, Will explores the topic of sustainability in inhalation devices:

Everyone should be cognizant of the climate crisis. The widespread general awareness of climate change and furthermore, the environmental impact an individual has is a growing consumer purchasing motivator. Thankfully, this heightened environmental concern isn’t just in the minds of consumers and device users but also starting to be mandated by large organizations and governing bodies too.

SDG’s, CMO’s, Pharma and Sustainability:

In 2015, all United Nations Member states adopted the 2030 Agenda for Sustainable Development. This ambitious program consists of 17 Sustainable Development Goals (SDGs), which are an urgent call for action by all countries and organisations. There are a number of goals directly relating to environmental impact, including;

12. Responsible Consumption and Production

13. Climate Action

14. Life Below Water

15. Life on Land

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The United Nations 17 Sustainable Development Goals, 2015

In the inhalation sector, many organizations are working hard to achieve not only the Sustainable Development Goals, but also their own sustainability initiatives (some actually coming online BEFORE the 2015 SDG program). Some organizations have released new devices and schemes to combat factors such as; polluting propellants, excessive material use, modular electronic add-ons and end-of-life device management. For example, in 2012 GSK introduced the Complete the Cycle recycling program for GSK’s respiratory Inhalers.

The Current Inhalation Device Landscape:

To understand the potential environmental impact of inhalation, first we need to understand the devices themselves. There are 4 main types of inhaler devices; Pressurised Metered Dose Inhalers (pMDI), Dry Powder Inhalers (DPI) Breath Actuated Inhalers (BAI) and Soft Mist Inhalers (SMI).

A pMDI is a relatively simple inhaler device, consisting typically of 3 parts; a canister, a plastic body and a plastic cap (some also include a dose counter indicating to the user how many doses are remaining in the canister). pMDI’s deliver the medicine in a spray aerosol form. Typical pMDI’s are Airomir and Salamol.

Relative to a pMDI, a DPI inhaler is more complex in design. When opened, it looks like the inner workings of a clock with various spools for medication as well as various plastic gears and cogs with a much larger plastic housing.

DPI’s deliver medicine in a dry powder state instead of a spray. Typical DPI’s are Accuhaler and Turbohaler.

A BAI is similar to a pMDI however, it’s the actuation of breathing or inhaling that activates the device to deliver the medicine. Typical BAI’s are Easi-Breathe and Autohaler.

SMI’s are more complicated versions of dose counting pMDI’s consisting of multiple small plastic components. SMI’s deliver the medicine in a fine mist that gets released from the device much slower than a pMDI. Respimat SMI is a typical example of an SMI.

Each of these inhaler types have their pros and cons. Some are only compatible with certain drugs while some are more user friendly and others are more readily available in certain markets. Generally, in the UK pMDI’s are the most popular (80% of inhaled corticosteroid devices are pMDI’s) however, it’s been noted that people are cautious of using pMDI’s due to their history of containing Chlorofluorocarbon’s (CFC’s), a gas that contributes to the depletion of the ozone layer and a contributor to climate change. CFC’s are no longer included in pMDI’s as a result of the 1987 Montreal Protocol initiating the phasing out of ozone-depleting substances.

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Core statistics on inhalation devices:

So, if pMDI’s don’t have CFC’s included, do they still have a significant environmental impact? What about the other types of devices?

It’s worth noting that 4% of the NHS’s entire carbon footprint comes from asthma related drugs. This is not an insignificant amount… In an investigation by the BBC, it was concluded that 5 doses of a pMDI is equivalent to a 9 mile car journey!

Approximately 75% of GSK’s Seretide MDI’s carbon footprint comes from the HFC-134a propellant. This shows that the propellant is the majority cause of environmental impact. R&D teams are racing to combat this factor, with Koura developing HFA-152-a and Honeywell developing HFO-1234-ze(E). These aren’t quick fixes and will take time to come to market due to canister and valve design changes. However, these are promising developments to reduce overall environmental impact.

While both DPI’s and SMI’s contain more plastic and are typically larger in size than pMDI’s, their total equivalent CO2 per dose is ~10x less than pMDI’s. The increase in plastic and device complexity does generally make DPI’s more expensive to produce.

What else has been done to mitigate the environmental impact of inhalation devices?

The Ellen MacArthur Foundation has developed what’s called the Butterfly Diagram to help illustrate the general truth regarding sustainable strategies:

 

In the diagram, the looping arrows on the right showcase the typical amount of energy or inefficiency in a sustainable strategy, showcasing that where possible, keeping devices in use for longer is typically the most sustainable strategy. This is easier said than done in medical device development and, with current devices and regulations this isn’t always permitted.

There are many ways to reduce the environmental impact of inhalation devices, all with different impacts and considerations to factor for. Thinking about the various stages of the life cycle of a device is incredibly important, knowing what the scope of reducing environmental impact is, whether, Cradle-to-Gate, Cradle-to-Grave, or Cradle to Cradle:

Strategy & Design:

Most of the influence regarding lowering the impact of a device is done via design strategy. Eliminating the root cause of pollution by design is the ‘easiest’ sustainable strategy of all. In engineering, there is a common phrase “Design casts the longest shadow”. Typically, design influences ~70% of the cost while materials influence 20% and labor 5%. Strategizing early on to design an inhaler with the lowest possible CO2 per dose from a cradle-to-cradle perspective would be a great initiative to strive for. If considering the development of a connected device, it is strongly recommended to modularize the function of the device and to purposefully separate the electronics from the disposable elements of the device.

Materials:

Utilising modern ‘ultra-sustainable’ materials in the design is a strategy well worth considering. Ideally, no new materials and plastics should be used to truly have the lowest possible environmental impact however, this is not always practical. Therefore, strategies such as using mass balance polymers, easily recyclable polymers, mono-material assemblies and reduction in material use (to name a few), are all useful strategies to employ.

Manufacture:

The manufacture of a device is where 100% of the actual environmental impact is typically observed even though, as previously discussed, it is not necessarily the fault of the factory nor machine operator. But still, there are ways to reduce the environmental impact of inhalation devices throughout the manufacturing stage. One potential radical strategy is distributed manufacturing and, making the devices on the same continent as where the devices are being used. Another may be to switch to hydraulic injection moulding machines, vs electric. And another may be to ensure that the energy used for the manufacturing process is generated from renewable sources such as solar or wind.

Transport & Packaging:

As with manufacturing, transportation can have notable impact on the sustainability of devices. Reducing the journey time between delivery points A & B is one potential strategy. Another strategy is using sustainable modes of transportation, such as last-mile electric trucks and lorries. Packaging the devices in environmentally friendly cartons, bags or boxes can also have a big impact. Minimising the number of materials required for packaging and increasing the ratio between the Volume of Goods: Volume of Packaging can also be beneficial in addition to understanding the supply chain constraints, end-of-chain manual handling and storage is incredibly useful.

Use:

Ensuring that the inhaler is actually used significantly affects its environmental impact. Otherwise, it’s a waste of energy and resource. Increasing the adherence and persistence of inhaler use is incredibly important for several reasons. This can be achieved early in the strategy and design stage, ensuring that the device is as easy to use through utilising user insights and effective Human Factors Engineering (HFE) strategies such as Formative Human Factors Studies. Providing Health Care Professionals (HCPs) with easy training materials such as clear instructions for use and potentially trainer devices could contribute to a greater adherence and persistence. Being able to track inhaler usage can greatly inform HPCs and even CMO’s and/or Pharmaceutical companies regarding the efficacy of their devices and inform decisions for next-generation solutions.

End of Life Management:

Knowing what to do with your old inhaler can be quite confusing and sometimes misleading. Some people say that they’re recyclable, some say they’re not, some people say that if you remove the plastic parts you can put them into household recycling bins, some say that they should be taken back to the pharmacy to be disposed of safely.

Informing the user in a clear manner regarding the disposal of their devices is incredibly useful to reduce the overall environmental impact of inhalation devices. There are lots of consumer products, especially in the food packaging industry that instruct the user to remove plastic film from the cardboard packaging prior to recycling.

NHS England encourages the use of local and manufacturer-led inhaler disposal schemes; however, they have no plans for a national inhaler recycling scheme. There have been and are several recycling programs to deal with the magnitude of inhaler device wastage. Approximately 73 million respiratory inhalers are prescribed every year in the UK.

Chiesi Leicestershire Take Air Recycling Program is a scheme launched in 2021 whereby any inhaler brand and type is accepted. Users send their old devices via prepaid postage to a waste disposal company for responsible recycling of components.

In 2012, GSK launched the Complete the Cycle program, a scheme (which has now closed down) that resulted in the recovery and recycling of 2 million inhalers, saving an estimated equivalent worth of 8,665 cars emissions in one year. The closing of the program is disappointing however, shows that it is possible and there are a lot of small local programs popping up to help reduce the end-of-life management of these devices.

Conclusion:

That being said, are we doing enough? Can more be done in the inhalation sector to reduce the environmental impact of these devices? How can we strive to make devices that are equally designed for both people and the Planet?

It’s clear to see that more can be done to reduce the environmental impact of inhalation devices, and it’s great to see that a lot of companies are taking the initiative to do so via an array of strategies. However, it’s important to note that we cannot overlook the importance of efficacy and safety when addressing sustainability issues. The environmental impact of a person having an asthma attack and requiring medical assistance has a much wider impact than whether an inhaler contains 5% less plastic.

Engineering and device development is a game of compromises and sometimes conflicting requirements… One cannot blindly pursue reducing the environmental impact of a medical device without having to carefully consider a multitude of other incredibly complex factors.

This does not mean that reducing the environmental impact of inhalation devices should be stopped, but rather should be understood in a more holistic approach. Understanding that different device types are better suited for different people. Understanding that this cannot be tackled in isolation but should be tackled in collaboration, be it device development teams, manufacturers, material scientists, transportation and logistics organizations, healthcare professionals, users, local councils or recycling centers.

At Haughton Design, we believe that legislation is ultimately the only way that some large organizations are going to embrace the drive to reduce environmental impact. Imagine if organizations were forced to consider post-cradle-to-gate solutions, publish their LCA data freely or, produce Product Environmental Footprints for every device that they manufacture, what would the world of inhalation devices look like? What would the world look like?

At Haughton Design we take a holistic and forward-thinking approach to medical device development carefully and responsibly considering each design decision across key project stakeholders. Having worked on inhalation device projects for many years, we understand the complexity of the development process however, by using Haughton Designs Development Workflow, we aim to simplify this process and responsibly accelerate your medical device development. Please get in touch to discuss how we can help with your medical device development.

William Morris - Senior Design Development Engineer & Business Development Manager at Haughton Design Will Morris 30 November 2022

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Get in Touch with Will Morris

Senior Design Development Engineer & Business Development Manager

Will graduated from the University of Wolverhampton with a degree in Product Design. Prior to Haughton Design, Will worked for Renishaw, where he led the industrial design for the current and next generation metal Additive Manufacturing machines. Will has a strong interest in Design for Sustainability, and the Circular Economy, looking to reduce companies’ environmental impact and often teaches about design engineering at local STEM events. Outside of work, Will enjoys Formula 1, rugby and travelling with friends.

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