Reactor Volume Is the Number in the Press Release. Solvent Throughput Is the Number That Sets the Ceiling.

Reactor volume is what appears in a capacity announcement. Solvent throughput is what determines whether that reactor can be run at nameplate. The two are not the same number, and the gap between them is widening as peptide demand scales.

The most useful public benchmark is the 2024 Process Mass Intensity study published in the Journal of Organic Chemistry by fourteen member companies of the ACS Green Chemistry Institute Pharmaceutical Roundtable. Covering 40 synthetic peptide processes at varying development stages — 34 of them SPPS, alongside four LPPS, one hybrid, and one chemo-enzymatic route — it remains the most comprehensive assessment of peptide environmental metrics available.

What the Data Shows

Findings from the ACS GCI Pharmaceutical Roundtable PMI study (J. Org. Chem. 2024, 40 peptide processes) and CDMO Hub analysis of public CDMO disclosures.

• SPPS averages a PMI of approximately 13,000 kg of material input per kg of API — against a median of 168–308 for small molecules and roughly 8,300 for biopharmaceuticals.
• Peptides are the most material-intensive major modality in commercial production. The Roundtable's separate oligonucleotide assessment places that modality at an average of approximately 4,300.
• Solvents are the single largest contributor to that figure, and synthesis and purification are the two most material-intensive stages.
• A single 31-residue GLP-1 analogue involves well over one hundred solvent exchange operations before the crude peptide is cleaved — around 30 couplings, 31 Fmoc removals, and a substantially larger number of intermediate washes.
• EU restriction is not prohibition. The REACH Annex XVII entries covering DMF, NMP, DMAC, and NEP condition continued use above 0.3% on exposure control and documentation. They convert solvent use into a compliance-and-capex question, not a ban.
• Capacity is set by the supporting assets, not the reactor. Tank farm, distillation train, and waste permit each carry their own throughput ceiling; a larger SPPS reactor does not raise output if any of them saturates first.

The Material Problem, Quantified

The 13,000 figure is an average across processes at differing stages, scales, and boundary definitions, not a benchmark for any single commercial campaign. It should be read as an order-of-magnitude statement about the modality rather than a target any one manufacturer is measured against.

The arithmetic behind it is not exotic. Each amino acid addition in Fmoc SPPS requires coupling, deprotection, and multiple wash steps, each using fresh solvent to drive reactions to completion and remove excess reagent. The exact count is set by reactor design, washing strategy, and scale. Downstream, preparative reversed-phase chromatography consumes acetonitrile at a rate that, on a mass basis, can become comparable to and in some cases exceed the entire synthesis stage.

The Solvent Set, and Its Regulatory Trajectory

The point most often missed

The current EU restrictions impose no blanket prohibition on the solvents that peptide manufacturing depends on; above a 0.3% threshold they condition continued use on exposure control, documentation, and operational requirements. They convert solvent use into a compliance-and-capex question: exposure monitoring, closed transfer, containment engineering, and documented risk management.

The competitive consequence is that solvent-heavy processes become more expensive to operate in Europe long before they become impossible — which is a sourcing variable, not just an ESG one.

Where Solvent Becomes a Capacity Constraint

Scaled against those PMI figures, a commercial peptide facility plausibly consumes solvent in the millions of litres per year. Manufacturers do not publish facility mass balances, so that should be treated as an order of magnitude rather than a disclosed figure. That volume has to be stored, delivered, recovered, requalified, and — for the fraction that cannot be recovered — treated or incinerated. Each of those is a separately sized asset with its own throughput ceiling.

Installing a larger SPPS reactor does not raise output if the tank farm cannot feed it, the distillation train cannot keep pace with the return stream, or the waste contract is at its permitted limit.

This is visible in how the leading players describe their own expansions. PolyPeptide's 2025 doubling of SPPS capacity at Malmö was reported alongside the installation of a new tank farm — the solvent infrastructure is treated as part of the capacity investment, not as a utility. Sourcing teams evaluating a quoted "300 L reactor" or "x tonnes per annum" figure should treat solvent recovery and waste headroom as the more informative constraint.

Who Is Actually Moving: A CDMO Scorecard

Public evidence of solvent performance is uneven. Some companies disclose audited environmental targets but little process detail; others publish process innovation but no facility-level metrics. The table below separates what is independently documented from what is a company or vendor claim, because the distinction matters when these statements are used in supplier selection.

The Constraint Nobody Prices In: Filed Processes Are Locked

Almost all of the technology above is straightforwardly available for new programmes. Very little of it is available for approved products. A solvent change in a commercial API process is a regulatory variation requiring comparability data, impurity-profile justification, and, depending on scope and market, prior approval. For a GLP-1-class product supplying multiple territories, the change-control cost can exceed the operating saving by a wide margin.

The consequence is a bifurcated market. Existing commercial volumes — which is where the tonnage is — will continue to run DMF-based SPPS with recovery and containment bolted around it. Solvent-lean technology will win on programmes still in development, where the process is not yet fixed. Any CDMO claim of a step change in environmental performance should therefore be tested against a specific question: on which programmes, at which stage, and is the process already filed?

Diligence Questions That Produce a Real Answer

• PMI per kg of API, broken out by synthesis, purification, and isolation — and whether the figure is measured from commercial batch records or modelled from development data. Ask what the boundary includes: water, cleaning solvents, chromatography buffers, recovery losses, and waste-treatment inputs are treated inconsistently between companies.
• Solvent recovery rate by stream. Ask separately for DMF and acetonitrile: what percentage is recovered, and of that, what percentage is requalified for GMP reuse rather than down-cycled to a lower-grade application or incinerated?
• Recovery headroom against nameplate. At what annual output does the distillation train, tank farm, or waste-treatment permit saturate? This is the number that governs whether quoted capacity is real.
• DNEL compliance evidence for DMF (entry 76) and NMP (entry 71) at EU sites and, ahead of the December 2026 deadline, for DMAC and NEP (entries 80 and 81) — plus what equivalent controls apply at non-EU sites in the same network.
• Platform dependency. Is the standard process DMF-dependent, or is there a validated greener alternative already used in GMP campaigns — not just demonstrated at laboratory scale?
• Purification architecture. Batch RP-HPLC or continuous/MCSGP, and acetonitrile consumption per kg of API at the purification step specifically.
• Assurance status. Are environmental figures externally assured or SBTi-validated, or self-reported? PolyPeptide is the only company in this review with publicly disclosed SBTi validation.

Why This Matters for Peptide Buyers

1. Quoted capacity is not effective capacity. Reactor volume and tonnes-per-annum figures describe the vessel. Solvent recovery rate, requalification rate, and waste headroom describe what can actually be run through it, and they are the numbers that govern whether nameplate is reachable.
2. European capacity carries a compliance cost that non-EU capacity does not. The REACH entries do not prohibit DMF, NMP, DMAC, or NEP; they condition their use on DNEL documentation, exposure monitoring, and containment engineering. DNEL-compliance capex and waste permitting are the gating items on European expansion.
3. Solvent-lean technology wins on programmes not yet filed. A solvent change to an approved commercial process is a regulatory variation, and the change-control cost frequently exceeds the operating saving. Route selection is where this decision is actually made.
4. The pull is coming from customers, not regulators. The two largest peptide innovators are both investing in lower-solvent routes. CDMOs serving them will be asked for the same metrics, and the ones that can answer in PMI per kg, recovery percentage, and requalification rate will be the ones that answer first.

The CDMO Hub View

Three distinct competitive positions are emerging, and they are not interchangeable. Disclosure leadership (PolyPeptide) matters most to listed sponsors with Scope 3 reporting obligations, who need supplier data they can consolidate. Process leadership (Bachem, CordenPharma) matters most to sponsors making a route-selection decision before a process is filed, where a lower-PMI platform converts directly into lower long-run cost of goods.

Downstream and isolation innovation (PeptiStar with Asahi Kasei, and the wider Japanese equipment base) matters where energy cost, cycle time, and heat-sensitive molecules dominate — an area with less competitive noise and, currently, less recognition than it merits.

Our expectation is that solvent performance will not displace price and capacity as the primary selection criteria within this planning cycle. What it will do first is act as a differentiator between otherwise comparable bids, and as a hard constraint on European capacity expansion where DNEL-compliance capex and waste permitting are the gating items. The CDMOs that quantify their position now — in PMI per kg, recovery percentage, and requalification rate — will be the ones able to answer the question when it becomes a scored line item rather than a conversation.

A Note on Scope

This briefing covers solvent use, recovery, and environmental performance in commercial peptide API manufacture. It does not assess overall CDMO quality, capacity, compliance history, or commercial terms, and inclusion or omission should not be read as a recommendation. Companies are discussed on the basis of publicly available information; absence of published data is not evidence of poor performance, and several manufacturers with substantive solvent-recovery programmes do not publish figures.

Where reported effects originate from a company or technology vendor rather than an independent source, this is stated in the table. Figures described as targets are commitments, not achieved results. The throughput argument advanced here is CDMO Hub's analytical conclusion drawn from public disclosures: no manufacturer publishes the facility-level solvent-feed, recovery, and waste-permit data that would demonstrate saturation against reactor nameplate directly.

CDMO Hub Insight

The next phase of competition among peptide CDMOs will be decided less by who has the largest reactors than by who can keep them running. Solvent supply, recovery capacity, and waste headroom now determine effective throughput, and they are measurable long before they are marketable.

For outsourcing teams, one question separates a real capacity figure from a quoted one: at what annual output does the tank farm, distillation train, or waste permit saturate? A CDMO that can answer it has measured its own ceiling. One that cannot has quoted a reactor.

Looking for peptide manufacturing partners? CDMO Hub helps biotech and pharmaceutical companies identify verified peptide CDMOs based on manufacturing capabilities, regulatory experience, scale, and therapeutic modality. Explore verified suppliers and peptide manufacturing capabilities.

Inside Peptide Manufacturing is a CDMO Hub series on the industrial side of the peptide category — capacity, chemistry, cost of goods, and the decisions that sit behind them.

Sources

• Peptide process mass-intensity benchmarks: Kekessie et al., "Process Mass Intensity (PMI): A Holistic Analysis of Current Peptide Manufacturing Processes Informs Sustainability in Peptide Synthesis," J. Org. Chem. 2024, 89, 4261–4282. Oligonucleotide comparison: Andrews et al., J. Org. Chem. 2021, 86, 49–61.
• EU solvent restrictions (DMF, NMP, DMAC, NEP): Commission Regulation (EU) 2021/2030 (REACH Annex XVII entry 76); Commission Regulation (EU) 2018/588 (entry 71); Commission Regulation (EU) 2025/1090 (entries 80 and 81).
• Dichloromethane (US): US EPA, Methylene Chloride; Regulation Under the Toxic Substances Control Act, final rule effective 8 July 2024.
• Green-solvent chemistry: Martin et al., Green Chem. 2021, 23, 3295–3311; Jadhav et al., Green Chem. 2021, 23, 3312–3321; Egelund et al., ACS Sustainable Chem. Eng. 2021, 9, 14202–14215; Jadhav, Seufert, Lechner, and Schönleber, CHIMIA 2021, 75, 476–479.
• Bachem MCSGP and TAPS: Bachem knowledge-centre disclosures. Reported solvent and yield effects are company figures.
• CordenPharma continuous SPPS and tag-assisted synthesis: CordenPharma press release, "CordenPharma Collaborates with PeptiSystems on Continuous Peptide Manufacturing and Green Chemistry," January 2022; CPHI Pharma Awards 2025 announcement, 28 October 2025. The 40% figure is a technology-vendor claim.
• PolyPeptide targets and disclosure: PolyPeptide Group Annual Report 2024 (2023 carbon-footprint and target tables), Annual Report and Sustainability Report 2025, Half-year Report 2025. Figures are validated targets, not achieved results.
• Jitsubo Molecular Hiving™: Jitsubo Co., Ltd. technology and news disclosures. No peer-reviewed head-to-head PMI comparison published.
• PeptiStar FO–MD installation: Asahi Kasei press release, 25 June 2026. Trial operation under evaluation toward GMP production.
• Innovator routes: "Kilogram-Scale GMP Manufacture of Tirzepatide Using a Hybrid SPPS/LPPS Approach with Continuous Manufacturing," Org. Process Res. Dev. 2021, 25, 1628–1636, and WO 2024/112617.

Figures and characterisations are current as at August 2026. Corrections are welcomed and will be carried in the following issue.