Producing clinical supplies for a first-in-human study is only the beginning of a drug product’s formulation journey. If Phase 1 trials demonstrate promising results and the program progresses into Phase 2, the scale and complexity of development increase rapidly. Phase 2 studies typically involve far more patients—often 100 or more—and are frequently conducted across multiple clinical centers and countries. As development progresses, the priorities for dosage form development begin to shift. While flexibility is essential in early-stage studies, later phases require formulations that can be manufactured efficiently, scaled reliably, and ultimately support commercial supply.
For this reason, many oral development programs transition to a tablet formulation as they enter Phase 2. Tablets offer clear advantages in terms of manufacturability and scalability, making them a logical step toward the larger production volumes required for pivotal Phase 3 trials and eventual commercial launch. Establishing an appropriate formulation at this stage helps ensure that the drug product can be produced consistently and efficiently as development progresses.
The difference in scale between early clinical development and commercial manufacturing is immense. First-in-human trials rarely require more than around 1,000 doses to complete the study and conduct the necessary analytical testing.
Commercial production operates on a completely different scale. Manufacturing processes must be robust, reproducible, and capable of producing very large volumes of product. In modern tablet manufacturing, production lines may generate hundreds of thousands of tablets per hour. Moving from small clinical batches to this level of manufacturing requires careful planning and well-designed processes.
Changes in the behavior or handling characteristics of the API can present significant challenges during this transition. As a result, close alignment between drug substance and drug product development teams is essential. Whether these teams operate within the same organization or across external partners, effective communication and coordination help ensure that development decisions support both early clinical needs and long-term manufacturability.
In the past, pharmaceutical companies often developed separate formulations for each phase of clinical development. A Phase 2 formulation would typically only be initiated once the results of Phase 1 trials were known. This cautious approach helped avoid unnecessary development work if the clinical program failed at an early stage.
Today, however, the industry seeks to accelerate development timelines. As a result, formulation work for Phase 2 is often initiated while Phase 1 trials are still underway. Activities such as excipient compatibility studies and formulation screening are conducted in parallel with clinical studies, allowing developers to move more quickly into the next stage if the early data are positive.
Ideally, the Phase 2 formulation should more closely resemble the intended commercial product than the simple formulations commonly used in early trials. Developing a scalable formulation at this stage can help reduce the need for major changes later in the development process.
Platform formulations can sometimes help streamline the transition to later-stage development. If the properties of the API allow it to be incorporated into an established formulation platform, development timelines may be shortened considerably. This approach can reduce the amount of formulation optimization required and provide a faster route to a manufacturable dosage form.
Drug loading plays an important role in determining whether such an approach is feasible. When drug loading is relatively low—for example around 10%— even poor powder flow properties can be acceptable, which can simplify formulation development as the API may integrate relatively easily into such an existing formulation platform. However, higher drug loadings may require more extensive development work to achieve the desired manufacturability and product performance.
As development progresses toward Phase 3, the dosage form and manufacturing process must be capable of supporting large-scale production and global regulatory approval. The formulation used in Phase 3 trials should be the same one intended for commercial launch, otherwise time- and cost intensive clinical bridging studies are often needed. Consequently, the manufacturing process must demonstrate a high degree of robustness, reproducibility, and scalability.
Even when development proceeds smoothly, creating a complex tablet formulation and process often requires between nine and eighteen months of development work, as also long term stability in various climatic zones needs to be ensured. During this time, developers must also ensure that sufficient quantities of drug substance with the appropriate quality attributes are available to support both clinical trials and commercial manufacturing.
Once the first representative manufacturing batches have been produced, formal ICH stability studies can begin. Earlier in development, accelerated degradation studies are often used to gain rapid insights into the stability of the molecule. However, at this stage of development, full ICH stability programs are required to generate the long-term data needed for regulatory submissions.
Packaging selection is another important consideration during this phase. Developers must identify a primary packaging solution that adequately protects the product from environmental factors such as moisture and oxygen while avoiding unnecessary complexity or cost. In many cases, relatively simple solutions such as aluminium blister packs may provide sufficient protection. More complex packaging approaches are only required when the product’s stability demands additional safeguards.
Once sufficient stability data have been generated and the formulation has been finalized, the product can be transferred to the commercial manufacturing site. At this stage, process validation and process performance qualification activities are conducted to demonstrate that the manufacturing process can consistently produce product that meets the required quality standards. The resulting data form an important part of the regulatory submission package.
Successful late-stage development depends heavily on the work carried out during the earliest phases of the program. Thorough characterization of the API, including a detailed understanding of its physical and chemical properties, provides the foundation for effective formulation development.
When this early work is insufficient, developers may encounter significant challenges later in the process. For example, selecting a suboptimal salt form or polymorph can introduce stability or manufacturability problems that may only become apparent during scale-up or long term stability. There are cases where salts were selected out of habit rather than because they are genuinely required to improve the properties of the molecule.
Such decisions can have far-reaching consequences. If a formulation must be redesigned or a different solid form selected at a later stage, development timelines may be delayed significantly—sometimes by a year or more.
Many companies are understandably cautious about investing in early development work, particularly given that most molecules entering Phase 1 will not reach the market. However, insufficient investment at the early stages can create substantial challenges for the small number of candidates that do ultimately succeed.
Careful early characterization of the API and thoughtful formulation development may increase upfront costs, but these investments often pay off later by reducing the risk of delays during scale-up and late-stage development. In the long term, taking the time to build a strong scientific foundation can be one of the most effective ways to accelerate the overall path to market.
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