By Wu Zhang, Year 12
The pharmaceutical industry has traditionally relied on complex, synthetic pathways to obtain a variety of drugs that are essential in advancing several fields, including medicine. However, in the process, large amounts of hazardous solvents are produced, and it requires energy-intensive reactions that are unsustainable for our planet. Therefore, as the global consensus shifts toward sustainability, the pharmaceutical industry faces increasing pressure to reduce its environmental footprint while still maintaining its crucial provision of drugs in various fields.
As mentioned, drug production is often resource-heavy, including but not limited to multi-step organic syntheses that generate significant chemical waste, particularly from solvents, and rely on harsh reagents or heavy metals. In large-scale manufacturing, this waste raises both environmental and economic concerns, as improper disposal can damage ecosystems and treatment processes increase production costs. A striking example of a place severely impacted by toxic waste from pharmaceutical production is Sakhi Lake (India), as well as the surrounding industrial region (Patancheru/Bollaram) — a chemical and drug manufacturing hub in Hyderabad, India. A 2021-2022 study found that “Pre-monsoon water temperatures hit a scorching 32°C, while pH levels fluctuated between 6.9 and 7.7. Dissolved oxygen levels plummeted to as low as 2.9 mg/l, dangerously close to the threshold where aquatic life begins to suffer”. All these values differ significantly from their recommended values. These conditions are similar in many other different parts of the world, leading to eutrophication, massive fish kills, and contamination of groundwater and soil in many different parts of the world.
Hence, this is when green chemistry comes in: a field focused on designing chemical processes that minimise waste, energy use, and toxicity has emerged as a powerful strategy to make drug synthesis more efficient and environmentally responsible. The principles of green synthetic processes were first introduced by John Warner, former president of the Warner Babcock Institute for Green Chemistry, and Paul Anastas, from the US Environment Protection Agency in 1998; their vision was guided by the 12 principles of green chemistry, providing a framework for designing new chemical products, covering all aspects of life cycles (raw materials, toxicity, biodegradability of products and reagents etc…).
Some major areas of green chemistry and how they work:
Biocatalysis is one of the most promising innovations in sustainable pharmaceutical chemistry, using enzymes to carry out reactions with exceptional selectivity and far fewer unwanted by-products. Because enzymes can distinguish (unique active site) between enantiomers (isomers which are mirror images of each other and non-superposable- see more about this in the article about fragrance organic chemistry), they often eliminate the need for complex chiral-resolution steps. Furthermore, their ability to function at room temperature and near-neutral pH significantly reduces energy use compared with traditional methods. They also avoid many hazardous reagents, replacing heavy-metal catalysts or strong acids and bases with cleaner, biological alternatives. A well-known example is the improved synthesis of the antidiabetic drug, sitagliptin, where an engineered transaminase enzyme (involved with amino acid metabolism and protein synthesis) replaced a rhodium (Rh) catalyst, cut waste production by 19%, and increased the overall yield, showing how biocatalysis can boost both sustainability and efficiency in drug manufacturing.
Solvents account for the largest portion of waste in pharmaceutical manufacturing, and many commonly used organic solvents (e.g. dichloromethane) are volatile, flammable, and harmful to the environment. To address this, pharmaceutical chemists are applying green chemistry principles to reduce solvent use and replace hazardous solvents with safer alternatives. Strategies include minimising the number of solvent-intensive steps in a synthesis, substituting greener options such as water, ethanol, or biodegradable solvents for traditional petroleum-derived ones, and implementing closed-loop recycling systems that allow solvents to be purified and reused rather than discarded. These approaches have already improved processes in the production of several antibiotics, where replacing chlorinated solvents with water-based systems significantly reduced toxicity and simplified waste treatment without compromising reaction efficiency.
Continuous-flow chemistry is another important innovation in green pharmaceutical chemistry, in which reactions are carried out continuously in small, controlled reactors rather than in large batch processes. This approach offers several advantages: improved heat control reduces side reactions, the smaller scale decreases energy use and safety risks, and continuous production minimises waste. Additionally, flow chemistry makes it easier to integrate greener catalysts and solvents (connecting the 2 previously mentioned methods) into the synthesis process.
In conclusion, green chemistry is transforming pharmaceutical manufacturing by making processes cleaner, safer, and more efficient, while also reducing costs, energy use, and waste. Innovations such as biocatalysis, greener solvents, and flow chemistry help chemists design drugs in ways that minimise environmental impact and simplify production, ultimately making medicines more accessible globally. As the field continues to evolve, sustainable pharmaceutical practices promise not only to improve human health but also to protect the planet, demonstrating that scientific innovation and environmental responsibility can go hand in hand.
Works Cited
Anastas, Paul, and John Warner. “12 Principles of Green Chemistry.” American Chemical Society, 2024, www.acs.org/green-chemistry-sustainability/principles/12-principles-of-green-chemistry.html.
Kumar, Rakesh, and Aarati Maurya. “Green Chemistry Techniques for Sustainable Pharmaceutical Synthesis.” Journal of Drug Discovery and Health Sciences, vol. 1, no. 04, 2024, pp. 187–200, https://doi.org/10.21590/jddhs.01.04.02.
—. “Green Chemistry Techniques for Sustainable Pharmaceutical Synthesis.” Journal of Drug Discovery and Health Sciences, vol. 1, no. 04, 2024, pp. 187–200, https://doi.org/10.21590/jddhs.01.04.02.
Lynch, Julie, et al. “Dichloromethane Replacement: Towards Greener Chromatography Via Kirkwood–Buff Integrals.” Analytical Methods, vol. 15, no. 5, 2023, pp. 596–605, https://doi.org/10.1039/d2ay01266a.
Rajani, Amisha. “Hyderabad’s Sakhi Lake under Threat, Chokes on Pharma Waste.” The Times of India, Times Of India, 22 Sept. 2024, timesofindia.indiatimes.com/city/hyderabad/hyderabads-sakhi-lake-under-threat-chokes-on-pharma-waste/articleshow/113563908.cms.
—. “Hyderabad’s Sakhi Lake under Threat, Chokes on Pharma Waste.” The Times of India, Times Of India, 22 Sept. 2024, timesofindia.indiatimes.com/city/hyderabad/hyderabads-sakhi-lake-under-threat-chokes-on-pharma-waste/articleshow/113563908.cms.
Rajani, Amisha, and ETPharma. “Sakhi Lake under Threat, Chokes on Pharma Waste.” ETPharma.com, ETPharma, 23 Sept. 2024, pharma.economictimes.indiatimes.com/news/pharma-industry/sakhi-lake-under-threat-chokes-on-pharma-waste/113581460. Accessed 12 Dec. 2025.
—. “Sakhi Lake under Threat, Chokes on Pharma Waste.” ETPharma.com, ETPharma, 23 Sept. 2024, pharma.economictimes.indiatimes.com/news/pharma-industry/sakhi-lake-under-threat-chokes-on-pharma-waste/113581460. Accessed 12 Dec. 2025.
Savile, C. K., et al. “Biocatalytic Asymmetric Synthesis of Chiral Amines from Ketones Applied to Sitagliptin Manufacture.” Science, vol. 329, no. 5989, June 2010, pp. 305–9, https://doi.org/10.1126/science.1188934.
Stefanache, Alina, et al. “Green Chemistry Approaches in Pharmaceutical Synthesis: Sustainable Methods for Drug Development.” AppliedChem, vol. 5, no. 2, June 2025, pp. 13–13, https://doi.org/10.3390/appliedchem5020013.
—. “Green Chemistry Approaches in Pharmaceutical Synthesis: Sustainable Methods for Drug Development.” AppliedChem, vol. 5, no. 2, June 2025, pp. 13–13, https://doi.org/10.3390/appliedchem5020013.
