Primum non nocere applies not only in medicine: an ecological look at inhalers
According to estimates from the World Health Organization (WHO), around 65 million people worldwide suffer from mild to moderate forms of chronic obstructive pulmonary disease (COPD). The cornerstone of therapy is the inhalation administration of bronchodilator drugs. While there is no doubt that this therapy helps patients, what impact do the propellants in inhalation systems have on the global climate? And is there a sensible solution to this problem?
Historical Perspective on Inhalation Systems
A milestone in the modern era of inhalation therapy is considered to be the year 1956, when a system based on the pressurised metered-dose inhaler (pMDI) was created. Propellants used included freons, or chlorofluorocarbons (CFCs). These were stable, cheap substances but, as later proved, had a high potential for damaging the ozone layer. For this reason, the use of CFCs as propellants was banned from 2005 based on the amended Montreal Protocol. In the pharmaceutical industry, they were replaced by a group of fully fluorinated hydrocarbons, known as hydrofluoroalkanes (HFA).
Propellants and the Greenhouse Effect
Both groups, CFCs and the newer HFAs, are also officially classified as greenhouse gases. They have the ability to absorb escaping infrared radiation from the Earth, trap heat in the atmosphere, and thus strengthen the greenhouse effect. Compared to CFCs, the impact of HFAs on the formation of the greenhouse effect is much lower, but still 100—3000× higher than that of carbon dioxide. Each type of HFA remains in the atmosphere for various durations, typically ranging from decades to hundreds of years, during which they release CO2. Emissions of HFAs from pressurised inhalers thus represent a considerable contribution to negative climate changes.
To quantitatively describe the impact of individual substances, the so-called global warming potential (GWP) is used. Norflurane (HFA-134a), one of the most widely used propellants in pMDIs, has a GWP value of 1300 over a 100-year horizon, meaning that when released into the atmosphere, it has the same effect as 1300 molecules of CO2.
Carbon Footprint
An important comparative factor is also the carbon footprint. This represents the sum of greenhouse gases released into the atmosphere during the production and use of a specific product, contributing to the undesirable warming of the planet. This includes medicinal products, so their carbon footprint can also be calculated.
Each year, about 630 million HFA-based pMDIs are produced worldwide. Considering the number of patients using this type of inhaler, the number of packs each patient uses during their lifetime, and the subsequent waste in the form of canisters with HFA residues, the impact on the climate is significant. The UN's goal is to reduce overall greenhouse gas emissions and limit global warming by 1.5 °C by 2030, which also calls upon pharmaceutical companies to take action.
The Advantages of Respimat for Patients and the Environment
One way to reduce the carbon footprint of pressurised inhalers is by replacing them with dry powder inhalers (DPIs). However, such inhalation systems are not suitable for all patients. They require a certain breathing effort, a quick and deep inhalation, which many patients are unable to perform.
A suitable solution might be an inhalation system technology that allows the release of medication from the canister using pressure but without the use of a propellant gas. The Respimat system meets this condition. The mechanism includes a spring creating mechanical pressure, driving the medication through very fine nozzles and forming a mist with an ideal droplet size.
For Spiolto Respimat and Spiriva Respimat products, the release mechanism of the dose counter is used repeatedly, and only the medication canisters (cartridges) are replaced. In the case of a 3-month pack, the product's carbon footprint can be reduced by 57%, and by up to 71% for a 6-month pack. This represents a significant difference compared to single-use pMDIs, which contribute to increasing HFA emissions with each consumed pack.
Additional beneficial properties of Respimat, such as a more accurate dose counter, a labeling window on the package, and simplicity of the inhalation maneuver, are thus combined with reusability and a reduced environmental impact.
(zemt)
Sources:
1. Sustainable improvements. Boehringer Ingelheim − Value Through Innovation. Available from: www.boehringer-ingelheim.cz/o-nas/udrzitelna-zlepseni/udrzitelna-zlepseni
2. What is a carbon footprint. CI2, o. p. s. Available at: https://ci2.co.cz/cs/co-je-uhlikova-stopa
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