PET recycled for anti-cancer drug manufacture

Researchers at a Scottish University have converted plastic waste into a key building block for anti-cancer drugs.

Currently, these types of medication are created using fossil-derived feedstock, often with reagents that produce significant and hazardous waste. The team from the University of St Andrews has recycled household polyethylene terephthalate (PET) scrap, such as plastic bottles, using a chemical ruthenium-catalysed, semi-hydrogenation process. This depolymerises the PET into ethyl-4-hydroxymethyl benzoate (EHMB). 

Environmental benefits

EHMB is a key intermediate for synthesising several important compounds, including the blockbuster anti-cancer drug imatinib; tranexamic acid, the base for medication that helps the blood to clot; and the insecticide fenpyroximate. 

This groundbreaking research, published as a paper in the journal Angewandte Chemie International Edition, is seen as offering substantial environmental benefits compared to conventional industrial methods for producing EHMB. Additionally, researchers discovered that EHMB can be converted into a new and recyclable polyester.  

Promising feedstock

Lead author of the paper, Amit Kumar from the School of Chemistry at St Andrews, says recycled PET is a promising new feedstock for generating high-value active pharmaceutical ingredients and agrochemicals.

‘Although chemical recycling is a key strategy for building a circular economy, many current technologies lack strong economic feasibility. By enabling the upcycling of plastic waste into premium products instead of reproducing the same class of plastics, such processes could meaningfully accelerate the transition to a circular economy.’ 

The chemical and pharmaceutical company Merck KGaA, which is a partner in the research, adds: ‘Pharmaceutical manufacturing generates substantial amounts of waste per kilogram of product, highlighting the urgent need for innovative sustainable chemical processes and raw materials with reduced environmental footprints.’