ABSTRACT: The use of medical devices such as needles, syringes, and inhalers for drug delivery is a well-established and vital part of the worldwide healthcare strategy. Traditionally such drug delivery routes have relied upon single-use plastics and high carbon footprint hydrofluoroalkanes (HFAs) to achieve effective and safe delivery to the user. In this article we outline design approaches that can be taken to develop sustainable drug delivery devices. Those include efficient device design to minimise waste, smart labels and instructions, modular packaging and smart supply-chains.
Every day 14,000 tons of medical waste are generated at healthcare facilities across the US alone. Up to 20-25% of this waste can be attributed to plastic packaging and plastic products . Increasingly there are movements towards sustainable packaging solutions in the consumer sector, but can such movements translate to the medical sector without compromising safety, efficacy and sterility of life-saving therapeutics?
Here we consider approaches to improve drug delivery device/packaging sustainability including designs to minimise carbon footprint and clinical waste.
We outline how such approaches can form part of our goal to help the healthcare sector achieve a circular economy where waste and pollution are designed out, products and materials are kept in use or reused, and resources enter a sustainable cycle with low or neutral carbon footprint.
EFFICIENTLY DESIGNED DRUG DELIVERY DEVICES
Two of the most common sources of single use plastic waste from pharmaceuticals are injectable and inhalable drug delivery devices. By their nature, these combined medical device/pharmaceutical products have stringent material and sterility requirements, making them difficult to recycle, and broadly unsuitable for reuse. Contaminated and drug contacting materials are classed as clinical waste after use and must be disposed of by incineration. As a result, the majority of the resources used in the manufacturing of these products are lost. Recently, Blue Planet and other documentaries have increased the awareness of patients & consumers of the damage caused by single use plastics. This is pushing the demand towards sustainable approaches.
Single use auto-injectors are popular for self-administration as the users are not in direct contact with the syringe or drug pre-injection. Auto-injectors are a more appropriate choice of delivery method for injectables that require precision and control in the injection process. They are simplified so it is easier to use - it is all prepared, requiring just a press of a button. This is particularly more relevant to emergency situations.
Single use auto-injectors are disposed of in a sharps bin as clinical waste, which is then incinerated. However, only the syringe is technically considered to be medical waste. Therefore, more of the device than necessary is being discarded as clinical waste.
An eco-friendly single use autoinjector can be designed by:
In the case of inhalers, the sustainability problem is two-fold. Firstly, traditional inhalers are made from plastics and metals, with facilities for inhaler recycle rare and underused, <1% of inhalers recycled, >60% end up in household waste  . Secondly, the most popular form of inhaler, pressurised metered dose inhalers (pMDIs) rely on hydrofluoroalkanes (HFAs) as the propellant gas, a greenhouse gas that contributes to pDMIs which has a carbon footprint equivalent of >500g/dose (>25 times that of DPIs) . However, asthma is a potentially fatal disease, and pDMIs are a proven technology, convincing users and clinicians to switch to greener alternatives is, therefore, far from straightforward.
This will require up-front investment from the industry to seek out alternatives, and to demonstrate equivalence of DPI or alternative inhalers in replacing pDMIs. Such steps may prove expensive, but with the ever-increasing pressure on the major pharmaceutical players to be seen contributing to sustainability, it may not be too long before such efforts make for a strong economic sense. Moving away from propellant based inhalers is not limited to DPIs. There is exciting, on-going research and development in the fields of jetting, nebulisation, pressurised liquids and vaporisation that would enable liquid based therapeutics for respiratory illnesses.
In the meantime, steps can be taken to make all inhalers in a more sustainable way. Drug contacting materials should be minimised, and facilities put in place to ensure they are disposed of appropriately (incinerated as clinical waste, not disposed with household waste). The design of the body of the inhaler needs to move toward a reuse and recycle model; active ingredient cartridges that can interface with the body and be swapped out. Such a move requires up-front investment in the robustness of the actuation mechanism, in establishing cleanliness and sterility protocols and in verifying the efficacy and dose control of a device over many years of repeated use. The materials of the body itself need to move toward durable plastics that are compatible with accessible recycling processes. Moreover, cooperation within the industry can help ensure universal compatibility of parts to avoid duplication. There is a path to a future with inhaler technology using sustainable materials, with waste minimised, and carbon footprint a fraction of its current size; however up-front investment is required on the part of pharmaceutical and medical device companies to embark on that journey ahead of anticipated future regulations that may enforce it.
SMART TECHNOLOGY FOR LABELS AND INSTRUCTIONS
Another significant contributor to wastage and the carbon footprint of drug packaging comes in the form of labelling and instructions that are normally printed on card or paper inserts. Instruction inserts such as these can be difficult to navigate. The result is often a voluminous set of instructions, hard to navigate for new users, discarded after a single use, or even without use, in the case of experienced users.
At PA, we are developing ways of reducing carbon contribution, while at the same time making the user experience more intuitive and streamlined. For example, QR code technology can allow for paper inserts to be reduced or eliminated altogether. Users can access the use instructions and other critical information about their drug via a quick tap on the QR scanner. Moreover, this allows the information to be categorised and searchable; the user does not need to search through pages of printed text instructions to confirm the dose or allergy information, they can tap straight to the relevant section. Taking this approach one step further, augmented reality can provide unprecedented improvements to the user experience by supplementing the user instructions with a full guided walk-through. For instance, by pointing a smartphone camera at an autoinjector, an app can identify the product and immediately impose graphics over the image pointing out the critical components of the device. The graphical overlay can then talk the user through a step-by-step guide to use and dispose of the device and can even remember if the user is using the device for the first time. Such an approach can even offer advantages to patient safety and outcomes, as the app can keep track of user critical parameters such as dose, time for next injection, product temperature and product reordering.
Making the transition to these smart labelling technologies is a journey that must be taken carefully; there is a risk that more vulnerable users could be left behind by the switch to smart tech. Additionally, the regulatory requirements for labelling and instruction differ geographically such that a single approach cannot be rolled out universally. However, as smartphone technology becomes adopted by an ever-greater proportion of the population, it will see smart labelling adopted more and more within the pharmaceutical industry. The benefits that these technologies can bring will be felt by the user, by the environment, and ultimately, will be driven by the economic advantages that the switch will bring to the manufacturers themselves.
MODULAR AND SUSTAINABLE PACKAGING SOLUTIONS
Packaging design is a significant challenge in the pharmaceuticals industry. Economies of scale make high volume drugs such as paracetamol or broad-spectrum antibiotics inexpensive to package in a manner that is efficient, and, ideally, environmentally friendly. However, in the case of low volume and low dose drugs, such as certain chemotherapies, and in the case of non-standard shaped pharmaceuticals such as auto-injector cartridges, the very low number manufacturing runs required mean bespoke packaging costs are high, and sustainability considerations often come second to the financial viability of the product. Such low volume packaging runs naturally have higher associated costs, and greater wastage associated with them.
At PA, we have been developing approaches for the industry to minimise low volume packaging costs and waste by switching to a modular approach to packaging. In its simplest form, modular packaging means replacing bespoke package designs with uniform packaging options to cover an organisation’s range of products, using standardised parts to make customised solutions. For instance, a typical pharmaceutical product may be packaged in an outer housing coupled to an insert to secure the product in place. The same box that holds 5 blister-packs can be adapted to hold 10 auto-injector cartridges by swapping out the cardboard insert within the box. By standardising the interfaces between the elements of a modular system it is possible to create wide compatibility across a range of products using only a small selection of inter-compatible modules, such as boxes and inserts. The advantages of such an approach are clear; the manufacturer can use the same selection of packaging for all products. End of run waste is minimised because modular components can be used on alternative products. The advantages extend further; shipping and storage costs are reduced by standardisation of packaging materials and dimensions. Individual packaging elements can be designed for reuse and recycle.
Modularity of design may also be coupled with selection of sustainable alternatives to traditional packaging materials. Paper and cardboard constitute a significant proportion of pharmaceutical and medical device packaging, but the reliance on single use plastics for blister packs and tamper/sterility seals limits sustainability. Recently, the Wasdell group has showcased a chemical treatment that creates biodegradable PVCs suitable for use in blister packs and related packaging , with the resulting treated PVC compatible with existing blister pack production lines. A range of other materials are being trialled for use in pharmaceuticals packaging, including biodegradable plastics such as polycprolactone (PCL), Polybutylene adipate terephthalate (PBAT), and Polyactic acid. Moreover, in instances where full recyclable materials are not feasible, due to the requirements of the drug, composite materials can also be used. This allows the use of a majority sustainable material, coupled to a thin layer (e.g. a polymer film). For example, natural fibre based pulps, such as cellulose, cotton or bamboo, providing the rigid structure of a package, coupled to a film of polypropylene (PP) or polyethylene terephthalate (PET) that can provide the moisture-proofing, gas permeability or other properties to the composite while still being up to 99% recyclable.
SMART SUPPLY CHAIN TECHNOLOGIES
Many pharmaceutical products rely on cold supply-chains in their distribution networks in order to reach their point of use with safety and efficacy maintained. Traditionally this has been achieved through the use of diesel-powered refrigeration vans and trucks, whose carbon footprint is up to 40% greater than equivalent transport in environmentally uncontrolled conditions . Smart technology can offer a greener alternative. Significant carbon emission savings can be realised over the traditional model by switching to a ‘charge and insulate’ model for cold goods transport. Instead of equipping vehicles with expensive, and diesel dependent, refrigeration equipment, storage containers can be ‘charged’ at a central location and distributed in an environmentally efficient manner. Charging involves using electrically powered cooling (i.e. compression) technology to cool and solidify Phase Change Materials (PCMs) with advanced thermal properties. These PCMs can be introduced to specially designed containers, that provide insulation from the environment, maximise thermal conductivity between PCM and product, while preventing chemical contamination of the pharmaceutical.
As well as carbon emission and cost savings, this approach offers greater flexibility: the temperature and size of each container can be chosen to suit the distribution needs, and products at numerous temperatures can be transported in separate insulted containers within the same vehicle, along with uncontrolled materials. The approach offers a green route to economic savings for the manufacturer and distributers by making regular shipments of environmentally sensitive products, in smaller batches, more feasible. The choice of PCM will depend on the specific application; temperature profile, container size, and distribution time. PCMs come in a range of materials including biopolymers and inorganics with high heat capacity and high latent energy. They can be reused and  they are already widely used in the automotive, electronics and heavy machinery industries.
The consumer sector is rapidly moving toward sustainability, largely driven by consumer choice. The pharmaceuticals and combined product sectors have, so far, lagged behind in this movement, in-part due to the complexities of pharmaceutical products, and in-part due to inertia and complacency. Eventually the industry will be compelled to green solutions by market forces, and those that innovate now will lead the next wave of pharmaceutical advances. As consumer and legislative pressures increase, and resources become more scarce and expensive, a circular economy movement will emerge, where resources enter a cycle that allows them to be reused and redistributed multiple times, with circular business practices playing a key role for the success. The businesses that minimise waste, and maximise resource utilisation through a combination of reuse, redistribution and recycling, will lead the way in the future economy. With this in mind, at PA, we have been striving to utilise materials to ensure the products we bring to market are developed in a sustainable, low-footprint way - we have started this journey with some of our pharma clients.
 Healthcare Plastics Recycling Council
 Nature: The environmental concerns driving another inhaler makeover https://www.nature.com/articles/d41586-020-01377-7
 NICE encourages use of greener asthma inhalers
 World’s First Biodegradable Blister Packs for Pills & Food Supplements Developed In Swindon
 Tassou S. A., De-Lille G., et al. Applied Thermal Engineering, 29(8-9), 1467-1477 (2009).
 SavENRG Phase Change Materials for Thermal Energy Storage