In August 2022 researchers proposed “GREENER” criteria for reducing the effects of medicinal residues on the environment. They suggest that healthcare “contributes 4.4% of worldwide greenhouse gas emissions”. Furthermore, active pharmaceutical ingredients (APIs) have environmental consequences. In particular, they take a toll on “aquatic ecosystems and drinking water resources”. The authors identify a potential conflict between the UN’s Sustainable Development goal (UNSDG) of “Good Health and Well-Being” and the UNSDGs “Life under Water” and “Clean Water and Sanitation”.  

Finding solutions 

One solution to the problem of API residues includes “the design and development” of APIs that are “intrinsically less persistent and less harmful”. Or, their “environmental risks are reduced” through “targeting and/or minimising drug use and reducing emissions after use”. However, it is essential during this process to maintain “therapeutic activity and patient safety”.  

Although we have established the One Health links between environmental and human health, there is “limited interaction” between experts. “Environmental scientists” and “drug discovery and development experts” must come together in a cross-sectoral approach.  

“Knowledge of environmental issues, sustainable pharmacy concepts, and relevant principles of green chemistry should be integrated into appropriate phases of the existing drug discovery and development process”. 

The GREENER concept 

The proposition “takes the natural environment as well as the patient into account”. Each recommended criterion promotes the reduction of the environmental impact of APIs after the patient use phase.  

Good practice for patients 

  • Well-being of the patient always comes first. This principle is often part of authorisation legislation. 
  • Medicines are required to be safe and efficacious in treating the disease.  

Reduced off-target effects, high specificity 

  • The mode of action of an API should be specific, in order to reduce possible side effects that an API can have on patients and on organisms in the environment. 
  • There should be a high margin of safety between pharmacological effects and adverse effects, reducing off-target effects. 

Exposure reduction via less emissions  

  • Reducing exposure can be achieved by less emissions after patient use. 
  • A possible solution is the development of new types of products such as low-dose APIs, personalised medicines, or better delivery methods to the target. 

Environmental (bio)degradability 

  • APIs and metabolites should not be persistent in the environment. 
  • They should preferably be transformed into non-persistent molecules in the sewage treatment plant or the natural environment, while still meeting stability requirements in the patient’s body.  

No PBT (persistent, bioaccumulative, as well as toxic) substances 

  • PBT substances may accumulate in food webs and could have long-term effects on ecosystems.  
  • When APIs meet PBT criteria, exposure reduction should be a goal.  

Effects reduction: avoid undesirable moieties 

  • Some APIs contain structural molecular moieties such as perfluorinated groups which present a potential risk to the environment. 
  • When designing new APIs, these molecular groups should be avoided if not central to the efficacy, safety, and delivery of the medicine to the patient.  

Risk and hazard mitigation 

  • When APIs are still expected to affect the environment, options for risk and hazard mitigation should be part of further product development. 
  • These can be found in other parts of the pharmaceutical use chain, like prescription, use, and waste.  

The paper concludes that the process will not be “straightforward”, acknowledging that APIs are “essential for healthcare”. They emphasise that the “benefits” of GREENER criteria must be weighed against “patient need, safety, efficacy, and costs”. The discussion, the authors note, is not over.  

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