“Sustainability should be understood as carbon, cost, and safety together. When a process becomes more efficient, you frequently improve all three.”— Celine Chen, VP and Head of PharmaBlock Europe
Pharmaceutical sustainability is no longer a compliance exercise, but a commercial and strategic imperative. The greatest decarbonization opportunity does not just lie in renewable energy or facility upgrades, but inside the chemistry and process design of drug manufacturing itself, explains Celine Chen, VP and Head of PharmaBlock Europe, and David Ennis, Executive Advisor, PharmaBlock; Former VP Chemical Development, AstraZeneca. This episode of the PharmaSource explores why green chemistry must lead the pharmaceutical decarbonization agenda, what buyers should demand from CDMO partners, and how forward-thinking manufacturers are connecting carbon intelligence with process excellence.
The Urgency Has Changed
“Companies are under increasing pressure from investors, regulators, customers, and society to show credible progress, not just ambition.”
David Ennis, Executive Advisor, PharmaBlock
Pharmaceutical sustainability has been on the industry agenda for years. What has changed is the nature of the pressure and the clarity of where the problem truly lies.
David frames this in two parts. First, there is a greater appreciation of urgency across the healthcare sector. “The climate crisis is the most urgent risk to human health,” he says, pointing to compelling data on the rising burden of chronic respiratory and cardiovascular disease, placing increasing strain on healthcare systems and their ability to pay for new medicines.
Healthcare itself contributes approximately 5% of global carbon emissions (more than the aviation industry), and pharmaceutical supply chains account for a significant portion of that figure.
Second, the industry now recognizes that the most substantial decarbonization opportunity is not inside company walls.
The distinction between Scope 1 and 2 emissions, which companies control directly, and Scope 3, which encompasses upstream supply chains, purchased goods, and services, has become central to this conversation. While many large pharmaceutical companies have made meaningful progress on their own operational footprints, Scope 3 emissions, particularly those embedded in purchased intermediates and active pharmaceutical ingredients, remain largely unaddressed.
“It’s important not just to focus on renewable electricity or site-level utilities — you have to address the biggest part of the problem.”
David Ennis, Executive Advisor, PharmaBlock
Why Decarbonization Is a Chemistry Problem
“If a process has too many steps, low yield, high solvent consumption, or difficult separations, then the carbon footprint is already being built into the process itself.”
Celine Chen, VP and Head of PharmaBlock Europe
Celine says the carbon footprint of a medicine depends more on the chemistry used than on the energy consumed.
“The majority of pharma’s carbon footprint is from Scope 3,” she explains, “and the majority of that Scope 3 footprint is embedded in purchased goods, which is embedded in how the molecules are made.”
“Even if you improve the energy mix later, the process may still remain inefficient from either a carbon or cost perspective,” Celine says. “That is why we believe decarbonization must start earlier: At the chemistry and process design stage. You need to ask: Can we redesign this route? Can we improve the reaction efficiency? Can we avoid the hazardous or wasteful steps? Can we apply green technologies, such as continuous flow or biocatalysis?”
Green chemistry, in this context, is not a niche technical discipline. “It is about redesigning the way that manufacturing happens,” Celine says. Technologies such as continuous flow synthesis, biocatalysis, process analytical technology (PAT), and computational modelling are the tools through which embedded carbon is reduced at the source.
From Commitment to Execution: Where Companies Struggle
The gap between sustainability commitments and operational reality is one of the most consistent challenges in pharmaceutical manufacturing today. David identifies several recurring friction points.
Missing Operational Pathways
“A common challenge is that many companies have targets, but they do not yet have enough operational pathways behind those targets to align people and activities,” David observes. Route selection, supplier engagement, process development, technology investment, and manufacturing network strategy all need to reflect sustainability priorities, and in most organizations, that alignment is still incomplete. “It is relatively straightforward to announce a goal. It is much harder to translate that goal into decisions.”
The Measurement Gap
Effective decarbonization requires two layers of measurement. “Many organizations still have only a high-level view of emissions; secondary data,” David notes. “That is useful for reporting, but it is not enough for decision-making. If you cannot see where emissions are generated at a process level, it becomes very difficult to know what to change.”
AstraZeneca’s investment in Life Cycle Analysis (LCA) across its product portfolio, identifying hotspots at the process level, is cited by David as a model for how organizations can move from data to action. “Once you have enough quality primary data to identify the most significant hotspots, you can move to action,” he says.
The Assumed Cost Penalty
Perhaps the most persistent misconception is that sustainability improvements will add cost or complexity. David recognizes that not all sustainability improvements will create immediate savings, but pushes back firmly. “In reality, the best solutions are often the ones that improve multiple dimensions at once. Shortening the synthetic route and improving process efficiency generally reduces cost, environmental impact, lead times, and improves productivity, robustness, and safety — all of which impact the value of a product.”
“The industry is maturing. People are increasingly looking for partners who can connect sustainability with process reality and value.”
David Ennis, Executive Advisor, PharmaBlock
What Sustainability Leadership Looks Like in Practice
For a CDMO or CRDMO, the distinction between genuine sustainability leadership and corporate rhetoric comes down to three concrete capabilities, as Celine outlines.
Carbon Visibility at the Process Level
“We need visibility into the carbon emissions of each module within a given process,” Celine explains. “Just like Dave mentioned, this calls for a cradle-to-gate LCA approach to Product Carbon Footprint, grounded in actual process data, not spend-based estimates, to pinpoint module-level emission hotspots.” Credible sustainability engagement begins with product carbon footprint data derived from real process parameters, not estimated from spend.
Technical Capability to Reduce Emissions
Identifying hotspots is necessary but insufficient. “If you want to reduce carbon at the process level, you need the tools to redesign chemistry, not just talk about targets,” Celine says. That includes continuous flow, process science, PAT, modeling, engineering, and increasingly biocatalysis and carbon intelligence.
PharmaBlock’s work in next-generation peptide manufacturing illustrates this approach. Conventional solid-phase peptide synthesis (SPPS) is highly resource-intensive, generating significant solvent waste and requiring reverse-phase chromatography at scale. The company’s integrated approach, combining liquid-phase peptide synthesis (LPPS), continuous-flow LPPS, and enzyme-assisted synthesis, has delivered dramatically lower solvent intensity. “Moving from SPPS to LPPS reduced DMF usage to less than one-twentieth of the original process,” Celine notes, “and helped avoid the burden of reversed-phase chromatography entirely.”
Transparency Across the Value Chain
“Transparency for us means not only helping customers identify product-level hotspots, but also engaging our own suppliers to better understand, manage, and reduce emissions across the broader chain,” Celine explains. A CDMO that helps customers identify hotspots in their products but remains opaque about its own supplier footprint is providing an incomplete service. “Taking responsibility for our own Scope 3 as a CDMO is essential,” she adds.
Continuous Flow: A System Capability, Not Just a Reactor Format
Continuous flow chemistry is frequently positioned as a novel manufacturing technology. In practice, its value is more fundamental.
“Continuous flow is important to us not simply because it is a different reactor format,” Celine says, “but because it enables a much more integrated way of developing and running chemistry.” For PharmaBlock’s technical teams, it represents an approach grounded in a deep understanding of reaction mechanisms, intrinsic kinetics, phase behaviour, and transport effects.
“Better process understanding and better engineering usually lead to better outcomes — lower by-products, improved yield, lower solvent and raw material consumption, enhanced safety, and more predictable scale-up.”
Celine Chen, VP and Head of PharmaBlock Europe
Continuous flow also opens access to broader chemical space. “High-energy, high-temperature, and very fast reactions that are difficult or unsafe to scale in traditional batch reactors become accessible,” Celine explains. “That allows more efficient production of building blocks, intermediates, and APIs that might otherwise be hard to manufacture at scale.”
Crucially, it is not a closed platform. “Continuous flow can be integrated with other green chemistry approaches, especially biocatalysis, including immobilized enzyme catalysis and enzyme-flow systems,” Celine says. “That is where we see a lot of future potential, because sustainable manufacturing will increasingly come from combining the strengths of chemistry, biology, and engineering.”
Carbon Intelligence: From Reporting to Decision-Making
The phrase ‘carbon intelligence’ risks becoming another piece of sustainability jargon. Celine explains what it means in practice.
“For us, carbon intelligence means moving from carbon reporting to carbon-informed decision-making,” she explains. It operates across four interconnected layers: Measurement and reporting to establish a credible process-level baseline; carbon attribution and optimization to understand which steps or inputs drive emissions most significantly; predictive modelling to compare scenarios before committing to routes or investments; and long-term data intelligence to build benchmarking and trend insight across projects.
“Carbon intelligence is not just a dashboard. It is a way to connect carbon with chemistry, engineering, and process choices.”
Celine Chen, VP and Head of PharmaBlock Europe
The practical implication for supplier engagement is significant. CDMOs that have invested in this infrastructure can provide customers with genuine input into product-level sustainability decisions, not just headline metrics for ESG reporting. “Once you understand a process, you can begin to compare scenarios,” Celine adds. “What happens to carbon performance if yield changes, if a step is redesigned, or if a batch process is replaced by continuous flow?”
What Buyers Should Be Asking
David offers a precise framework for pharmaceutical and biotech buyers evaluating CDMO sustainability credentials. Six questions cut through rhetoric to operational reality.
- Has the partner committed to the Science Based Targets initiative (SBTi) for carbon emissions and other nature-based targets, and is there evidence of progress, not just stated intentions?
- Can they measure carbon and waste at a process-relevant level using primary data, rather than spend-based estimates? This is increasingly important as sponsors will need this data to meet regulatory requirements in some key markets, such as the EU.
- Can they identify the real hotspots within a specific route or manufacturing process?
- Do they have the technical capabilities to reduce those emissions, route redesign, process intensification, continuous flow, biocatalysis, solvent recycling, and membrane technologies?
- Can they connect sustainability improvements to business impact (cost, robustness, quality, scalability, and supply reliability) rather than treating them as separate objectives?
- Do they have a credible approach to engaging their own upstream supply chains on sustainability, not just their direct processes?
The last point is particularly important. “It is not enough to ask whether a supplier has an ESG program,” David says. “The more useful question from a manufacturability perspective is whether they can help reduce the embedded footprint of the product itself.”
“Sustainability should be understood as carbon, cost, and safety together. When a process becomes more efficient, you frequently improve all three.”
Celine Chen, VP and Head of PharmaBlock Europe
