Puff Goes the Inhaler

One of my greatest passions is taking apart – and attempting to fix – mechanical pencils, pens, white-outs, and any other utensils I can get my hands on. It’s no surprise, then, that ever since I was first diagnosed with asthma and prescribed an inhaler, I have been fascinated by how it works. When I press the top of the device – specifically an AstraZeneca Symbicort Rapihaler metered-dose inhaler – a strong, consistent, mist-like aerosol launches into my throat. Lured by my curiosity, I tried prying open my inhaler. Removing the canister from the plastic casing was rather easy, only requiring a light pull. However, I faced a challenge when I realized the rest of the inhaler was soldered in place. Lacking a grinder and realizing that tearing open a pressurized canister was probably a terrible idea, I decided to call it a day. Nevertheless, my curiosity lingered. So, as anybody would do after an unsuccessful dissection, I decided to research how the components are made instead.

At the very start, bauxite ore is mined and refined into aluminum oxide through the Bayer process (Irish Environmental Protection Agency, 2019). Processes like these are developed by chemical engineers, who create and improve commercial methods to refine raw materials like bauxite ores. After being purified in China, which is the primary aluminum producer, it is shipped to another 3rd party factory where it is shaped into a canister (Government of Canada, 2023). This aluminum canister is then transported by cargo ship and truck to AstraZeneca’s Dunkirk production plant, where it is cleaned in preparation for filling.

In the case of my inhaler, it is filled with fluorocarbon additives, a steroid called budesonide, and a ß-agonist called formoterol fumarate hydrate. These chemicals have to be precisely synthesized while avoiding any dangerous isomers. This is the job of biochemical engineers, who develop synthesis pathways for organic compounds – in this case, medicine – starting from readily-available raw materials such as crude oil and its extracts. Working out of labs, they have to not only make sure that the products are pure enough to be used safely as medication, but also design pathways that are concise and do not include unnecessary steps.

Once the biochemical engineers find a viable synthesis pathway, it must be scaled for mass production. Process engineers are in charge of not only this scaling up process, but also optimize the pathways to be as efficient and economically viable as possible – without this crucial step, the medication would either be unaffordable to most asthmatics, or uneconomical to produce. After optimization, process engineers co-work with other professionals such as mechanical and robotic engineers who design and develop the machinery that will make their plans a reality. In AstraZeneca’s facility, robotic arms are used to precisely manufacture different components, fill the canisters, assemble the pieces, and perform quality control checks (Joseph, 2023, 1). Robotic engineers, together with the electrical engineers who determine how the robots will be wired to the factory’s grid, and software engineers who program the robots to carry out their myriad functions, play a crucial role in inhaler production – the innovations in accuracy and speed they have brought with their robots are one of the factors that help make affordable inhalers available around the globe.

Robotics is especially important when making metering valves, which are the lids for the canisters. Precisely designed by biomedical engineers, metering valves must release the inhaler medication uniformly, regardless of how much is left in the canister (Stein et al., 2013). As a result, each metering valve consists of numerous precisely-engineered parts, despite looking like little more than a simple lid once sealed.

While the medication and metering valves are being prepared, plastic mouthpieces and dose indicators, which display how much medication is left, are shaped from plastic pellets in smaller factories. Designed by petroleum engineers, these pellets originate from hydrocarbons, which are typically extracted from crude oil through either distillation or cracking. The processing and shaping most likely takes place in China, which is the world’s largest plastic producer, and the components are then transported to France by cargo ship – potentially even the same one that brought the aluminum canisters (European Environment Agency, 2022). Once the plastic parts arrive at the facility, the assembly process can begin. Canisters are fitted with mouthpieces and dose indicators, sealed, and packaged before leaving Dunkirk.

Once an inhaler leaves Dunkirk, it enters the realm of the logistics engineers. A three-to-four-hour truck ride takes the inhaler to the Port of Le Havre at the northern border of France, while logistics engineers plan the optimal maritime freight routes and make sure everything will arrive in time. This includes the trip the inhaler will make on a container ship ultimately destined for the Port of Busan, South Korea (Klinge Corporation, 2019). The logistics engineers are also in charge of figuring out plan Bs to account for any disruptions en-route. This was vital during the Covid pandemic – if there was a confirmed Covid case on board a cargo ship, the vessel would be transferred to South Korea’s Yeongdo Cruise Terminal for quarantine (Busan Port Authority, 2020), leading to a delay in arrival and possibly low inhaler stock levels. To prevent any disruptions or shortages, logistics engineers planned ahead of time and created contingency plans.

Now the Covid pandemic has diminished in severity, the inhaler can head by truck to its distribution center in Gyeonggi-do, just outside of Seoul, without worries of quarantine delays. Finally, small delivery trucks take boxes of inhalers to the pharmacy opposite my apartment, where they can be individually distributed to asthmatics and COPD patients.

My inhaler is typically emptied around two months after purchase, when it heads back to my local pharmacy’s used medicine collection bin. Once a sufficient amount of used medication is compiled, the inhaler will be collected by garbage trucks. Used medicine, unlike other waste, cannot be disposed of in landfills due to possible environmental effects – instead, my inhaler is destined to be burned at the Gangnam Resource Recovery Facility (Boxall, 2004). Facilities like this are meticulously designed by civil engineers to maximize efficiency while minimizing harmful effects on the environment and surrounding neighborhoods. A garbage truck drops the bag containing my inhaler and other garbage into waste pits. I always think of these pits as oversized claw machines, if the piles of trash were dolls and the gigantic excavator arm was a claw. Scooped up along with heaps of garbage into the incinerator, the inhaler ends its journey.

After a painstaking manufacturing process, almost a month aboard a container ship, and two months of usage, the incinerator almost feels like an unfitting final destination. However, my inhaler still has one last contribution: engineers have designed a system to recapture the heat generated from combustion and use it to spin the turbine in a nearby power generation facility, creating electrical currents with endless possibilities. As my inhaler transitions from plastic to electricity and pushes electrons throughout my neighborhood, it might end up warming my room, powering a neighbor’s dishwasher, or – after passing through multiple products – producing part of another medication, thus starting the cycle all over again.