Green Chemistry

The first principle of Green Chemistry states that waste should be avoided. Waste represents inefficiency. As dealt by subsequent principles of Green Chemistry, some reactions are inherently wasteful, producing by-products. Chemists will evaluate different ways of making target chemicals in order to reduce or eliminate by-products. This has a significant impact on chemical production because by-products and any other impurities need to be removed. The purification of chemicals usually creates a lot more waste.

Waste can also occur due to poor process or product design. Materials have value as long as they are useful. If products are made for single use, they inevitably become waste. Reusable items reduce waste, but it is not always simple to deploy them. They might be more expensive and new initiatives such as 'take-back schemes' might need to be in place. Medicines themselves are not reusable because they are used in the body, but other waste from the pharmaceutical and healthcare sector could be reduced through reuse or recycling. This includes discarded peripheral equipment (test kits, dispensers, syringes, etc.), expired products, packaging and manufacturing waste. Changes to the design of medical equipment might allow them to be sterilised and reused. Improved recycling infrastructure would improve packaging recycling rates.

Waste treatment is not technically a core discipline within Green Chemistry because the objective is to eliminate waste. However, it is obvious that we are far from achieving this aim, and so waste management remains important. When considering waste management is important to refer to the Waste Framework Directive (or analogous legislation in your region) This directive proposes the waste hierarchy, which recommends how to reduce the depletion of natural resources and prevent environmental degradation. The waste hierarchy in the context of pharmaceuticals is explained below.

Reuse is not an obvious route to waste prevention in terms of pharmaceutical products, but it could be applied to dispensers and packaging. In manufacturing, reaction catalysts are often reused.

Recycling is routinely performed on packaging via household waste collections, but it also applies to manufacturing plants. Solvents can be recycled by distillation. More can be done to improve recycling rates with specific design innovations and improved, more widespread recycling infrastructure. This is being encouraged through policies such as the circular economy.

Recovery usually refers to waste incineration where energy is reclaimed, often by heating water to drive a steam turbine. Materials are rated as more valuable than energy, which is why recovery is after recycling in the waste hierarchy. After all, a recycled material could be incinerated (with energy recovery) later once one more use has been acquired from it.

Disposal in landfills, or litter, is an unacceptable loss of material value and should be avoided. Pharmaceuticals are metabolised as part of their intended function and excreted. This form of disposal is unavoidable. When chemicals are released into the environment as part of their function, they shall be biodegradable, and ideally made from renewable resources too. Then they are compatible with a circular economy. Incineration without energy recovery is also categorised as disposal because no value is retained. Many single use medical devices will be incinerated because of contamination. Public health must be the priority but in some instances sterilisation could be more appropriate.