Shincy Jacob, Priyanka Salunkhe and Dr. Subhashis Chakraborty, ACG Capsules, spotlight the overlooked functional attribute shaping patient-centric capsule design.
ACG Capsules
As patient-centric drug delivery continues to reshape formulation strategy, much of the industry’s attention has been on complex delivery systems, novel excipients and advanced release mechanisms. Yet one of the most practical – and potentially impactful – attributes of oral solid dosage forms is routinely overlooked: the ability to open a capsule.
Hard capsules have long been valued for their versatility in formulation development. But their structural design, a separable cap and body, offers a level of flexibility that extends well beyond manufacturing considerations and into how medicines are actually taken. As the industry places increasing emphasis on adherence, accessibility and patient experience, that feature is gaining renewed relevance.
It is also a feature that sets capsules apart from tablets in a meaningful way. A compressed tablet is, by design, a fixed and intact unit; it cannot be opened or divided without potentially compromising the dose or the formulation. A hard capsule, by contrast, is inherently separable. That structural difference has real clinical relevance, particularly for patients who cannot swallow solid dosage forms whole.
From formulation feature to patient need
Swallowing difficulties (dysphagia) affect a significant proportion of patients, particularly in the paediatric and geriatric populations. For many of these individuals, conventional oral administration presents a genuine barrier to treatment. The ability to open a capsule and administer its contents with a suitable food vehicle, commonly known as sprinkle administration, offers a practical and well-established route around this.
Regulatory authorities recognise this approach, provided that comparable drug exposure can be demonstrated between intact and modified administration. As a result, a growing number of commercially available products, spanning both immediate-release and modified-release formulations, are now being designed with this flexibility in mind.
Yet awareness of capsule openability remains surprisingly low. Patients and caregivers are often simply unaware that capsules can be intentionally opened under appropriate conditions, a disconnect that highlights a gap between what formulation science makes possible and how medicines are actually used.
A well-established but under-recognised practice
A review of marketed pharmaceutical products indicates that sprinkle administration is already well established across a wide range of capsule-based formulations. This is not an emerging concept; it is an underutilised one.
The implication is clear: while the industry has developed products that support flexible administration, the practical benefits are not always fully realised across the board. This gap between design and use raises important questions about how dosage forms are communicated, prescribed and ultimately experienced by end users, the patients.
Understanding openability
To explore this further, ACG conducted a qualitative evaluation to assess the manual openability of selected hard capsule variants. The study involved 40 participants and focused on whether capsule size and shell polymer type influence the ease of cap–body separation.
Gelatin and cellulose-based capsules in sizes #3 and #4 were selected, representing
commonly used formats that may also present handling challenges due to their smaller size. Importantly, the evaluation was designed to reflect typical user handling conditions rather than controlled mechanical testing, offering insight into real-world usability.
The findings revealed variability in perceived opening effort across participants and capsule types. However, no consistent or reproducible trend could be established linking manual openability to specific design variables such as size or polymer composition.
Instead, the results point to an interesting conclusion: manual openability is not solely a function of capsule design but is significantly influenced by user-dependent factors.
The role of human factors in dosage form design
Grip strength, dexterity, handling technique and individual familiarity all played a role in determining how easily participants could open capsules. This highlights the importance of considering human factors in dosage form design.
In practice, this means that two patients using the same product may have very different experiences depending on their physical capabilities and confidence in handling the dosage form. For those already facing challenges with administration, that variability can have a direct impact on adherence and treatment outcomes.
Formulation considerations and limitations
The suitability of alternative administration depends heavily on the formulation itself. Exposure of capsule contents to external environments, such as food, can influence drug stability or alter release characteristics. This is particularly relevant for modified-release systems, where the integrity of the formulation is critical to achieving the desired profile.
As a result, alternative administration strategies must be evaluated on a product-by-product basis. For modified-release formulations, this may require dedicated bioequivalence studies to ensure that opening the capsule does not compromise drug performance. In contrast, immediate-release products may present fewer risks, depending on the nature of the active ingredient and excipients.
Regulatory guidance reflects this distinction, typically recommending in vivo evaluation of sprinkle administration when such use is indicated in reference product labelling.
Bridging the awareness gap
While many individuals within the study appreciated the ability to open capsules once demonstrated, several reported that they had not previously realised this was possible.
There is an education dimension here that the industry should not ignore. If patients do not know a capsule can be opened, that capability is effectively invisible to them, however well-designed the product. Greater awareness among patients, caregivers and prescribers would enable considerably more flexible use of capsule-based therapies, particularly in paediatric and geriatric settings where swallowing difficulties are most prevalent.
Clear labelling, patient instructions and healthcare professional guidance all have a role to play in bridging this gap.
Implications for formulation and development strategy
Taken together, these findings reinforce the need to view capsule openability not as a secondary feature, but as a functional attribute with wide-reaching implications for formulation scientists and product developers.
Rethinking capsule design in a patient-centric era
As the industry continues to evolve, ‘good’ dosage form design is no longer just about stability, efficacy and manufacturability - usability and adaptability now matter in equal measure.
Capsules are well placed to meet this shift. Unlike other oral solid dosage forms, they can be opened and adapted, offering flexibility for patients who struggle with standard administration.
What seems like a simple feature has real impact: for some patients, the ability to open a capsule can determine whether they even take their medicine at all.
As patient-centricity becomes a key differentiator, capsule openability highlights a broader shift towards dosage forms designed not just for delivery, but for real-world use.