Here are a selection of risks, and design features that we included to mitigate them:-
- Users might not understand the new system – Having looked at ways to separate the nozzle from the mouthpiece body, it was decided that pre-attaching it to the canister would mitigate a list of use related risks and provide a familiar device.
- Slow up-take of the proposed system due to production difficulties and investment needed – The new nozzle component clips around the canister, rather than onto the stem, which initially seemed like the obvious solution once we’d decided to pre-attach it to the canister. This means that no change would be necessary to existing canister production.
- A small nozzle could be inhaled through the mouthpiece – The nozzle is now larger than the mouthpiece, meaning that it’s impossible for it to be inhaled.
- The nozzle becomes stuck in the mouthpiece body and prevents a new canister being inserted – This was a key consideration in the design and there are several mitigating features. As we now have two connections (canister to nozzle and nozzle to mouthpiece body), we needed to ensure that when the canister is pulled out of the mouthpiece body, the nozzle can’t be left behind in the body. As a starting force, we physically tested the pull-out force of existing canisters, using our in-house equipment, and used this for the force to pull the nozzle from the mouthpiece body. For the connection between the nozzle and canister, this needed to be much greater to ensure that the nozzle isn’t left behind. Using FEA, the clips were designed in a way that the force to remove the nozzle from the canister would be much higher. A second mitigation was to position rib features in the mouthpiece body to constrain the nozzle clips from opening whilst it’s in the body. Thirdly, the canister stem could be used as a tool to release the nozzle through a small hole in the base of the mouthpiece body.
- Users have difficulty inserting or removing the canisters – Using our in-house test equipment, we understood the forces to insert and remove existing pMDI canisters and ensured that the new canister and nozzle would insert and remove in a familiar way.
- The nozzle needs to be inserted in the correct orientation – To ensure that the dose is directed through the mouthpiece, the mating cup feature for the nozzle, is angled in a way which rotates the canister into the required orientation without much input from the user. Visibility of the nozzle attachment is also available through the mouthpiece, or the body if it is produced in a clear material.
Aside from these technical features, the form of the inhaler has seen sharp edges replaced with softer, rounded edges, which make the inhaler feel better in the hand and much more comfortable to carry in pockets etc.
We believe we’ve designed a sustainable pMDI system that would feel like a relatively small change to users, but provide an impressive annual plastic reduction of approximately 80%. Across the UK and USA alone, this would be in the region of 1,500 tonnes of plastic!
EcoHale Dose Counter Concept
In 2003, the FDA released a guidance document that recommends new MDI developments to have a dose-counting device integrated within the product, that displays when the recommended number of actuations is approaching the end, as well as when it has reached or exceeded that number. For the US market in particular, we have applied our thoughts to how we could integrate a dose counter into the EcoHale concept, using the same philosophies of producing an easy to use, familiar, and safe system, that retains the benefits for the planet through reusability.
The dose counter concept is unique in that the counter is pre-attached directly to the canister, tying the available actuations and the drug together, which keeps the count even if the user swaps the canister into a different actuator body. Similar to how the use-by date is printed on to the canister label currently, to prevent this information from being separated from the drug.
As the dose counting mechanism would be disposable with the canister, this does have an impact on the plastic waste savings of the original concept, however, compared to a current fully disposable dose counting pMDI, the savings will still be very significant. Particular attention was paid to making the mechanism as small as feasibly possible and from a single material, while counting up to 200 doses!
We gained a high amount of interest in the original EcoHale concept, notably from the NHS, who can see the sustainability improvements and potential cost savings as well. We look forward to discussing EcoHale and the dose counter development and gaining support to take this project further, hopefully making a big difference to the sustainability of future pMDIs.