FLOW CHEMISTRY chemistry is registered with multiple authorities and any major change requires full justification, re-validation and new approvals. In many cases, the strategy becomes taking a sub-optimal but proven batch process through to commercialisation and, only after commercial success, investing in a second-generation process optimised for cost, scalability or sustainability.
Ultimately, the decision is a balancing act between minimising upfront costs and time to market, versus investing early in a more robust, long-term, and sustainable process with a lower cost of goods. The likelihood of success remains the central unknown. Batch processing remains the default for good reasons. Only when serious concerns about process safety or scale-up robustness arise is the door typically opened for flow chemistry.
Infrastructure, confidence & collaboration
CDMOs can play an active role in navigating the trade-offs in adopting flow chemistry. Customers will understandably raise practical questions around a potential flow process: What volumes can be handled? Can the process provide consistent quality? How will it impact timelines and budget? Can it be validated for commercial manufacturing? Ideally, some feasibility testing will have already been completed to allow a preliminary assessment of the potential benefits and risks.
While such concerns are valid, the success of flow chemistry implementation often hinges on a combination of experience, appropriate infrastructure and close collaboration between the CDMO and the customer. On the infrastructure side, modular design has become a common approach. Larger flow systems are reconfigured for different chemistries without requiring a complete rebuild for each new project.
In a regulated environment, all equipment must be qualified to GMP standards before use. Assembling bespoke flow systems introduces additional qualification requirements, which can be significant. However, this challenge can be partially mitigated by pre-qualifying individual modules. Once assembled, only the performance of the combined system needs to be demonstrated for the specific process in question.
Despite the extensive literature on flow chemistry, its routine application in commercial pharmaceutical projects remains limited. Technical information packages( TIPs) submitted by clients still rarely include flow-based processes.
However, this is beginning to change. Awareness of flow chemistry is increasing, and clients are becoming more open to exploring it and actively asking for flow chemistry, often prompted for improving safety, consistency or process intensification.
IP & exclusivity aspects
Developing both batch and flow chemistry processes involves building process understanding, adapting the underlying chemistry and applying targeted optimisation. However, flow chemistry brings an additional engineering dimension and typically draws on less prior art. This often creates greater opportunity to generate new intellectual property.
In earlier phases of adoption, the limited number of CDMOs with flow chemistry capabilities could also create a form of vendor lockin. For clients, this sometimes raised concerns about flexibility, particularly when considering future technology transfer.
In contrast, batch processes were often seen as easier to transfer at later stages, especially once the product reached commercialisation. These considerations may have historically tilted preference toward batch, particularly when long-term strategy and partner flexibility were key priorities.
Solids & heterogeneity
Flow chemistry systems are inherently small in scale and rely on narrow flow paths. One of the key limitations arises when solids are present, either introduced as part of the feed or formed in situ during the reaction, leading to clogging and blockages.
Most pumps used in flow systems are not designed to handle particulate matter, making this a significant technical challenge. A common
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