Quality by Design Is a Mindset, Not a Milestone
Lakshmi, Editorial Team, Pharma Focus Europe
Quality by Design has been embedded in European regulatory expectation for nearly two decades, yet it is still widely treated as a dossier section rather than an operating philosophy. This article examines why enhanced development approaches stall at the point of implementation, how analytical, sterility and post-approval frameworks have raised the stakes, and what boards must change to convert a compliance exercise into durable manufacturing advantage.
Introduction
Every medicine is a promise about consistency. The tablet dispensed in Milan next spring must behave exactly like the one tested in a trial four years earlier, and like the ten million made between them.
There are two ways to keep that promise. The first is to manufacture a batch and then test it — sampling the output, comparing results against a specification, releasing what passes and rejecting what does not. The second is to understand the process so thoroughly that the outcome is a predictable consequence of how it was designed. Which raw material characteristics matter, which processing conditions influence which product attributes, and what range each can move within before the product changes.
The second approach is Quality by Design. It was formalised in the harmonised pharmaceutical guidelines that Europe adopted from 2006 onward, and it rests on one deceptively simple principle: quality cannot be tested into a product — it must be built in by design, through systematic risk-based development that starts from predefined objectives and depends on product and process understanding, process control, sound science and quality risk management.
In practice, that means defining what the finished product must do for the patient, identifying the attributes that determine whether it does so, mapping the process variables that drive those attributes, and building a control strategy that holds them steady. The framework has since been extended through companion guidelines on quality risk management, the pharmaceutical quality system, and the development of drug substances.
None of this is contested. Nearly two decades on, the vocabulary appears in every European submission, every quality manual, every training deck.
The behaviour is another matter. In a great many organisations, Quality by Design happens once — during development, for the dossier — and then stops. The science is generated, written up, filed, and quietly abandoned the moment the product reaches commercial manufacturing.
That gap between the language and the practice is what European regulators have stopped tolerating, and it is what this article is about.
The Dossier Is Not the Product
The most common failure mode is elegant on paper and hollow in operation.
A development team constructs a design space during late-stage work. Critical quality attributes are identified, risk assessments are conducted, a design of experiments programme establishes ranges, and the resulting narrative is written into the submission. It is scientifically defensible and entirely genuine.
Then the product transfers to commercial manufacturing, and the design space becomes an archived document. Process changes are managed through deviation systems that never reference it. Operators run at setpoints, not within understood ranges. When a batch drifts, the investigation reaches for historical practice rather than the causal model the organisation spent two years building.
The knowledge was created. It was never institutionalised.
This is the difference between QbD as milestone and QbD as mindset. A milestone is completed and left behind. A mindset persists through technology transfer, scale-up, site changes, supplier substitutions, and the ordinary erosion of a decade of commercial supply. If the control strategy is not the living reference point for every manufacturing decision, the organisation has purchased regulatory language without acquiring regulatory capability.
Inspectors have grown adept at detecting the difference. The question is rarely "do you have a control strategy?" It is "show me the last three deviations and where the control strategy appears in your reasoning."
Where Enhanced Approaches Actually Fail
There is a persistent assumption that the enhanced approach failed to gain traction in Europe because it is expensive.
It is expensive. That is not why it fails.
It fails because the investment is front-loaded and the return is deferred, while organisational incentive structures are the reverse. Development leadership is measured on submission dates. Manufacturing leadership inherits the consequences. The team that would pay for deeper process understanding is not the team that would benefit from fewer post-approval variations, faster technology transfers, or the absence of a recall.
The result is a rational, locally optimal decision that is globally destructive: do enough enhanced development to satisfy the assessor, and no more.
The second failure is subtler. Many organisations construct design spaces they never intend to use — ranges claimed in the dossier but never exercised in production, because operating outside the historical setpoint feels risky to a quality unit that was not part of building the model. A design space that nobody dares operate within is a very expensive piece of prose.
Genuine QbD requires a quality organisation confident enough to use the flexibility its own science has justified. That confidence is cultural, not procedural, and it cannot be written into an SOP.
The Method Is a Product Too
For years, analytical procedures sat outside the QbD conversation entirely — developed pragmatically, validated once, and then frozen.
That exemption has ended. The analytical procedure development guideline, finalised in November 2023 and effective from June 2024, extends QbD principles to analytical procedures, completing the quality framework alongside the revised guidance on analytical validation. The European regulator has adopted it as a scientific guideline covering science and risk-based approaches for developing and maintaining analytical procedures used for release and stability testing.
The conceptual shift is significant and widely underestimated. Methods are increasingly treated as evolving assets — designed with intended purpose in mind, systematically challenged from a scientific risk perspective, transferred with greater understanding, and monitored throughout routine use — rather than as a fixed set of conditions followed by a one-off validation. Analytical quality by design places the analytical target profile, risk assessment, knowledge management and performance monitoring at the centre of method designThe commercial argument is stronger than the compliance one. Harmonised expectations are intended to reduce redundant work and conflicting requirements, bridging longstanding differences between pharmacopoeias, regulatory bodies and internal procedures that previously generated duplication — a European finished product requiring an impurity test absent from another region's acceptance criteria, for example.
For any organisation supplying multiple regions from a European site, method-level QbD is not an academic exercise. It is the difference between one analytical package and four.
Sterility Is Not a Room. It Is a Strategy.
Nowhere has the mindset-versus-milestone distinction been made more forcefully than in European sterile manufacturing.
The revised annex governing sterile medicinal products made the contamination control strategy a mandatory element, requiring organisations to move from siloed controls to an integrated, science-based framework in which risk analysis drives every contamination prevention measure — a shift demanding cultural change, cross-departmental collaboration and quantitative data.
Note the language: cultural change. Not documentation.
The annex positions the contamination control strategy as an integral part of the pharmaceutical quality system, replacing an earlier emphasis on discrete parameters — cleanroom grades, media fills, sterility test limits — with a proactive, holistic prevention framework, and explicitly requires that processes, equipment, facilities and manufacturing activities be managed according to quality risk management principles.
The inspection reality has followed. Inspectors now arrive expecting contamination control to be designed into the facility and demonstrable in real time, not evidenced through paperwork. And the recurring findings are instructive: weaknesses persist not because requirements are unclear, but because translating regulatory expectation into practical, sustainable control remains difficult — with contamination control governance, barrier technology performance, personnel behaviour and critical utilities emerging consistently as the decisive areas.
Three of those four are behavioural. Governance, personnel behaviour, and the discipline to maintain utilities are not capital problems. They are management problems, and they cannot be solved by a remediation project with an end date.
The Flexibility You Never Claimed
The most commercially painful consequence of milestone-thinking arrives years after approval.
Post-approval change management in Europe remains, for many organisations, an exercise in friction — variations filed, assessed, and awaited, for changes the manufacturer understood perfectly well were low-risk. The harmonised lifecycle framework was designed precisely to reduce this burden, allowing manufacturers who demonstrate genuine process understanding to define which parameters constitute established conditions requiring regulatory notification, and which can be managed within the pharmaceutical quality system.
The catch is uncomfortable: that flexibility is earned in development. An organisation that took the minimum-viable route to submission has no scientific basis on which to claim it. Ten years of unnecessary variations become the compounding interest on a decision taken to save six months at filing.
This is the clearest possible expression of why QbD is a mindset. The organisation that treated enhanced development as an investment holds an asset that pays out for the product's entire commercial life. The organisation that treated it as a hurdle pays a tax for the same duration.
Boards rarely see this trade-off, because the cost appears in operating expenditure years after the decision that caused it, in a different function, under a different leader.
Culture Is the Control Strategy
Strip away the acronyms and QbD reduces to a single organisational question: does this company believe that understanding its processes is more valuable than documenting them?
The answer is visible in small things. Whether process engineers are present at deviation reviews. Whether the quality unit can explain the mechanism behind a specification, or only its number. Whether an operator who observes something unusual is rewarded for reporting it or penalised for the paperwork it generates. Whether the control strategy is a document retrieved for inspections or a reference consulted on Tuesday afternoons.
The regulatory direction of travel makes this increasingly non-optional. Continuing evolution across continuous manufacturing, analytical development and validation guidance, expanded quality risk management training materials, alongside emerging approaches to advanced manufacturing technology and the European pharmaceutical legislative package, is placing new emphasis on quality-system robustness and global manufacturing resilience — while the core principle endures unchanged: quality must be built in, not tested in, and risks must be identified and controlled scientifically.
Organisations that internalised that principle are now well positioned for continuous manufacturing, real-time release, model-based control and the analytical technologies arriving behind them. Every one of these depends on process understanding as a prerequisite. None of them can be retrofitted onto a company that treats quality as an inspection outcome.
Conclusion
Quality by Design has never been a submission requirement disguised as a philosophy. It is a philosophy that regulators eventually wrote into requirements. Organisations that treat it as a milestone will keep passing inspections and keep paying for it — in variations, deviations, failed transfers and forfeited flexibility. Those that treat it as a mindset build understanding that compounds across a product's entire life. The distinction is cultural, and it starts in the boardroom.
Lakshmi is a science writer with a foundation in the laboratory. She earned her master's in biotechnology and trained through research internships at ICGEB (JNU) and DIPAS, DRDO, with her work appearing in the Egyptian Journal of Veterinary Sciences. Now APCRM-certified and part of the editorial team at Pharma Focus America and Pharma Focus Europe, she reports on pharmaceutical technology, research, and innovation — giving complex science a clear and confident voice for industry leaders.
